Abstract:
Some embodiments are directed to a battery. The battery can include a case having a hollow accommodation cavity formed therein. The case having a material that includes a blend comprising at least one of polysulfone, acrylonitrile butadiene styrene (ABS), Nylon, polyphenylene oxide (PPO), styrene-acrylonitrile (SAN), and polypropylene. The material of the case enables removal of thermal energy generated during operation of the battery.

Description:
BACKGROUND 
       [0001]    The disclosed subject matter relates to batteries. More particularly, the disclosed subject matter relates to composition of material of case of a battery, methods for removal of thermal energy generated by a battery, and methods for manufacturing case for a battery having high thermal conductivity. 
         [0002]    A power source, such as a battery, is used to provide electrical voltage to a number of electrical devices. The battery converts chemical energy into electrical energy that is provided to the electrical devices used in various fields, such as, automobiles, space and satellites, industrial machineries, weapon systems, etc. The battery can be divided into two categories: a primary battery that is a non-rechargeable battery and a secondary battery that is a rechargeable battery. Various applications require the need of using the secondary batteries for their operations, such that when reactants within the battery are exhausted, energy is restored within the batteries. The secondary battery provides various advantages, such as low internal resistance, cost effective, etc. 
       SUMMARY 
       [0003]    Use of rechargeable batteries have grown by leaps as global demand of upcoming technologies and their products such as laptops, mobile phones, computers, and other commonly known consumer electronic products has increased. In addition, interest in the rechargeable batteries used in the products has grown in order to support environmental issues such as, to conserve natural environment and resources and to curtail negative impacts of human activities. 
         [0004]    One of the major concerns with the products is thermal energy that is heat generated by batteries of these electronic products. The charge capacity of batteries is reduced overtime when exposed to high temperatures such as above 120 degree Fahrenheit (° F.) for extended period. 
         [0005]    In some related arts, batteries such as silver zinc cells are made out of injection molded thermoplastic cases by using materials such as polysulfone and acrylonitrile-butadiene-styrene. While, these materials feature outstanding stability in caustic electrolytes, they have poor thermal conductivity. Further, testing of these batteries during discharge shows high temperatures at the center of the batteries. 
         [0006]      FIG. 1A  represents a cross-sectional view of a battery  100 A in some related arts. The battery  100 A includes a polysulfone material case  102 . As shown in  FIG. 1A , heat generated by cells in the battery  100 A is deposited near the center  104  of the battery  100 A. During normal operation of the battery  100 A, a silver zinc cell heats up during charge-discharge cycles and gets overheated beyond a temperature limit. Therefore, battery  100 A of the related arts results in degradation of critical components of the battery  100 A. This further leads to reduced cycle-life of the battery  100 A. 
         [0007]    In addition, in some related arts, the rise in temperature within the battery often occurs in the middle of the case  102  from where the removal of the generated thermal energy that is excess heat becomes difficult. 
         [0008]    Some related arts, uses heat sinks within the batteries in order to remove the generated thermal energy. As shown in  FIG. 1B , a battery  100 B uses heat sinks  106  to remove the excess heat by transferring the heat from the battery  100 B to a suitable heat sink  106 . In some related arts, graphite is generally used as one of the materials in the battery  100 B to transfer the excess heat from the battery  100 B, as graphite has a thermal conductivity of 5.7 Watts per meter kelvin (W/mk). Material of the heat sink  106  based on graphite, have an in-plane thermal conductivity of over 1,700 W/mk, which can take the heat from between cells and the cell bottoms  102  to the heat sink  106 . Therefore, heat sinks made up of graphite when placed between the cells prevent heat from propagating between the cells in the battery  100 B. 
         [0009]    Further, some related arts use electrically insulative plastic in the battery  100 B having high thermal conductivity of 10 W/mk to remove the excess heat from the battery  1008 . However, just by adding highly conductive material without a heat sink is not effective. 
         [0010]    It may therefore be beneficial to provide a battery, and methods of use and manufacture thereof, that address at least one of the above issues. For example, in order to enhance thermal conductivity of a battery, a battery casing having high thermal conductivity can be configured and disposed within the battery. 
         [0011]    It may therefore be beneficial to provide methods and apparatus that address at least one of the above and/or other disadvantages. In particular, it may be beneficial to produce a cooling architecture of the case of the battery in order to remove excess heat from the battery. The excess heat within the battery is generated by exothermic reaction accompanying discharging of the battery. 
         [0012]    It may therefore be beneficial to provide methods and apparatus that address at least one of the above and/or other disadvantages. In particular, it may be beneficial to improve cycle-life of the battery to provide sufficient amount of electrical power to the electrical devices. 
         [0013]    It may therefore be beneficial to provide methods and apparatus that address at least one of the above and/or other disadvantages. In particular, it may be beneficial to increase safety of the battery to prevent generation of thermal energy that can degrade the performance of the battery. 
         [0014]    The configuration, size, shape, installation location and orientation, etc., of the battery can be varied depending on the type of application, etc., to provide electrical power. 
         [0015]    Some other embodiments are directed to a battery. The battery can include a case having a hollow accommodation cavity formed therein. The case of the battery can include a plurality of components for generating a voltage, wherein the one or more components generate thermal energy during operation of the battery. The case of the battery has a material that includes a blend comprising at least one of polysulfone, acrylonitrile butadiene styrene (ABS), Nylon, polyphenylene oxide (PPO), styrene-acrylonitrile (SAN), and polypropylene. The material of the case enables removal of thermal energy generated during operation of the battery. 
         [0016]    Yet other embodiments are directed to a method of producing a case for a battery. The method can include: preparing a mixture of materials, wherein the materials of the case includes at least one of polysulfone, acrylonitrile butadiene styrene (ABS), Nylon, polyphenylene oxide (PPO), styrene-acrylonitrile (SAN), and polypropylene; and blending the mixture of materials with thermally conductive polyphenylene sulphide. The blended mixture of the case enables removal of thermal energy generated during operation of the battery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee. 
           [0018]    The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given by way of example, and with reference to the accompanying drawings, in which: 
           [0019]      FIGS. 1A and 1B  illustrate related art battery case capable of removing excess heat from a battery in accordance with the disclosed subject matter. 
           [0020]      FIG. 2  is a model of a battery in accordance with the disclosed subject matter. 
           [0021]      FIG. 3  is a table illustrating properties of materials of the battery, in accordance with the disclosed subject matter. 
           [0022]      FIG. 4  is a table illustrating internal resistance of the battery determined from a cell discharge test, in accordance with the disclosed subject matter. 
           [0023]      FIG. 5  is a table illustrating heat generation calculation at 100% discharge of the battery, in accordance with the disclosed subject matter. 
           [0024]      FIG. 6  is a graph illustrating heat generation at 100% discharge of the battery, in accordance with the disclosed subject matter. 
           [0025]      FIGS. 7A-7F  illustrate finite element analysis and model results of the battery, according to various embodiments, in accordance with the disclosed subject matter. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0026]    A few inventive aspects of the disclosed embodiments are explained in detail below with reference to the various figures. Exemplary embodiments are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows. 
         [0027]    I. Battery Structure 
         [0028]      FIG. 2  is a model of a battery  200  that can include a cell case  202 , terminals  204   a - b,  hereinafter referred to as terminal  204 , electrode tabs  208 , etc. in accordance with disclosed subject matter. 
         [0029]      FIG. 2  illustrates the battery  200 , and embodiments are intended to include or otherwise cover any type of battery, including, but not restricted to, silver zinc, Li ion, Pb Acid, Ni Cd, Ni MH, metal-air cells (e.g., using Mg, Zn, Al, Cd, and Li as the anodes), Ni Zn and Ni Fe. In fact, embodiments are intended to include or otherwise cover configurations of the battery to provide electrical power to electrical appliances, such as electric vehicles, hearing aids, forklifts, cameras, etc. In some embodiments, the battery  200  can be an electrochemical cell. 
         [0030]    The battery  200  can include the cell case  202  of the battery  200 . In some embodiments, the cell case  202  is molded polysulfone. The properties of the molded polysulfone can make the cell case  202  tough and stable at high temperatures. Embodiments are intended to include or otherwise cover any shape or form of the cell case  202  with configurations that may be beneficial to provide stability at high temperatures. In accordance with some embodiments, the shape of the cell case  202  is generally rectangular having a length L, a width W, and a height H. However, the shape of the cell case  202  is shown as rectangular in  FIG. 2  for illustration purposes only, and the various embodiments are intended to include or otherwise cover any shape of the cell case  202  that may be beneficial. 
         [0031]    The battery  200  can include the terminal  204 . In some embodiments, each of the terminals  204  of the battery  200  can include three layers. The three layers of the terminal  204  can include, but not restricted to, an inside layer of silver tabs, a middle layer of solder, and an outside layer of brass. Silver wires may alternatively be used in place of the silver tabs. 
         [0032]    In certain embodiments, the terminals  204  of the battery  200  are modeled as squares. In alternate embodiments, the terminals  204  of the battery  200  are modeled as round. Embodiments are intended to include or otherwise cover any shape or form of the terminals  204  with configurations to provide electrical power to electrical products. In some embodiments, the terminals  204  of the battery  200  can be made up of copper, Ag plated steel, brass, tungsten, etc. Embodiments are intended to include or otherwise cover any material for terminals  204  with configurations that may be beneficial to transfer electrical voltage to electrical appliances. 
         [0033]    The battery  200  can include electrode tabs  208 . In some embodiments, the electrode tabs  208  can be positive tabs, and negative tabs. In alternate embodiments, the battery  200  can include a plurality of positive tabs, and a plurality of negative tabs. In some embodiments, the positive tabs of the plurality of electrode tabs  208  are grouped on one end of the battery  200  and terminate in a terminal. In certain embodiments, the hollow terminal can be a positive terminal. In some embodiments, the negative tabs of the plurality of electrode tabs  208  are grouped on another end of the battery  200  and terminate in a terminal. In certain embodiments, the terminal can be a negative terminal. 
         [0034]    In some embodiments, the positive tabs can be made from a variety of materials, such as, but not limited to, silver, nickel and/or silver plated copper. In some embodiments, the negative tabs can be made from a variety of materials, such as but not limited to, silver, nickel and/or silver plated copper. In some embodiments, the battery  200  can use substrates such as thin silver sheets to form the negative tabs. 
         [0035]    The battery  200  can include a plurality of separators. In some embodiments, the electrolyte  206  can be KOH, NaOH, and additives with the electrolytes such as ZnO and LiOH. 
         [0036]    In some embodiments, the battery  200  can include one cell. In alternate embodiments, the battery  200  can include more than one cell. 
         [0037]    The components of the battery  200 , such as the cell case  202 , the terminals  204 , the electrolyte  206 , the electrode tabs  208 , etc., are disposed in a cell pack  210 . In some embodiments, the cell pack  210  can include a number of identical cells. In certain embodiments, the cells in the cell pack  210  can be connected in series. In alternate embodiments, the cells in the cell pack  210  can be connected in parallel. In accordance with some embodiments, the shape of the cell pack  210  is generally rectangular having a length l, a width w, and a height h. However, the shape of the cell pack  210  is shown as rectangular in  FIG. 2  for illustration purposes only, and the various embodiments are intended to include or otherwise cover any shape of the cell pack  210  that may be beneficial to dispose a plurality of cells. 
         [0038]    In some embodiments, the cell pack  210  of the battery  200  can include a plurality of cell edges  212 . 
         [0039]    An exemplary battery, such as a silver-zinc cell, can include a cell case such as a plastic cell case. In some embodiments, the exemplary battery can include a plurality of positive electrodes, a plurality of separators, and a plurality of negative electrodes. In certain embodiments, the positive electrode, the negative electrode and the separator of the battery are disposed within the case of the battery. Each of the plurality of electrodes has a silver tab (or silver wire) welded to a top corner of the electrode. In addition, the positive tabs of the plurality of electrodes are grouped on one end of the battery and terminate in terminal. In an embodiment, the terminal can be a positive terminal. In some embodiments, the negative tabs of the plurality of electrodes are grouped on the other end of the battery and terminate in a terminal. In certain embodiment, the terminal can be a negative terminal. In some embodiments, the electrodes are filled with a solder anchoring the silver tabs (or wires). In some embodiments, the electrodes can be crimped or welded anchoring the silver tabs (or wires). The battery can further use substrates such as thin silver or copper sheets to form the negative electrodes of the battery. 
         [0040]    In some embodiments, zinc substrates have zinc powder on both sides except for the end plates, which can normally have the zinc or zinc oxide on a side facing the silver sheet. In certain embodiments, the positive tabs have silver or silver oxide on both sides of exmet substrates (i.e. mesh reinforcement). In some embodiments, two positive plates are wrapped in cellophane with bottoms of the plurality of electrodes facing each other to form a first U-shaped wrap. In some embodiments, the structure of the case of the battery can be built with a negative half plate external to the first U-shaped wrap, a double sided negative inside a second folded U-wrap, a double sided negative plate between the first and second U-wraps, a double sided negative plate, etc. until the case is completed with another half negative. The multilayers of cellophane can create a very high thermal resistance perpendicular to the plane of the electrodes. 
         [0041]    II. Methods for Manufacturing the Battery Case 
         [0042]    In some embodiments, the case  202  of the battery  200  can be made by using an injection molding process. The injection molding process can be used to produce the case  202  of the battery  200  by injecting a material into a mold. In accordance with some embodiments, the shape of the mold is generally rectangular having a length x, a width y, and a height z. However, the various embodiments are intended to include or otherwise cover any shape of the mold that may be beneficial to include or otherwise dispose components of the battery  200 . 
         [0043]    In certain embodiments, the material of the case  202  can be, but not limited to, thermoplastic material. The thermoplastic material can include, but not restricted to, polysulfone. In some embodiments, the material of the case  202  can be thermally conductive blended with a second material. In certain embodiments, the second material can be a Polyphenylene Sulfide (PPS). 
         [0044]    In some embodiments, the Polyphenylene Sulfide (PPS) can be thermally conductive blended with the materials such as polysulfone in order to produce the case  202  of the battery  200 . In some embodiments, the percentage of the PPS blended with the materials such as polysulfone can be 40. In alternate embodiments, the percentage of the PPS blended with the materials can be 60. In certain embodiments, the percentage of the PPS blended with the materials such as polysulfone can be in the range of 10 to 100, and preferably 40 to 60. 
         [0045]    A method for producing the case  202  of the battery  200  is disclosed, in accordance with disclosed subject matter. In some embodiments, a mixture of the materials is prepared. As discussed above, the materials can include, but not restricted to, polysulfone. 
         [0046]    Further, the prepared mixture can be blended with the thermally conductive material such as Polyphenylene Sulfide (PPS). In some embodiments, the mixture can be blended by using injection-molding process. 
         [0047]    The prepared mixture can then be poured into a mold to produce the case  202  of the battery  200 . 
         [0048]    In accordance with some embodiments, the shape of the cell case  202  is generally rectangular having a length L, a width W, and a height H. In alternate embodiments, the shape of the cell case  202  of the battery can be, but not limited to, square, sphere, cube, etc. However, the shape of the cell case  202  of the battery  200  is rectangular shown in  FIG. 2  for illustration purposes only, and the various embodiments are intended to include or otherwise cover any shape of the cell case  202  of the battery  200  that may be beneficial to accommodate a plurality of cells within the battery  200 . For example, the shape of the cell case  202  may be prismatic. 
         [0049]    Furthermore, in some embodiments, the structure of the cell case  202  can include a plurality of partitions. The plurality of partitions may be used to divide the cell case  202  into a number of regions. In certain embodiments, the plurality of cells are disposed within the plurality of regions of the case  202  of the battery  200 . 
         [0050]    III. Properties of Materials 
         [0051]      FIG. 3  is a table  300  illustrating properties of materials of the battery  200 , in accordance with the disclosed subject matter. The table  300  can include a part  302  of the battery  200 , material  304  of the part  302 , mass density  306  of the material  304 , thermal conductivity  308  of the material  304 , and specific heat  310  of the material  304 . 
         [0052]    As shown in table  300 , the cell case  202  can be made up of Polysulfone material having mass density 0.00011646 lbf*s2/in/in3, thermal conductivity of 0.0326376 in*lbf/(s*in ° F.) and specific heat of 1,034,179 in*lbf/(lbf*s2/in ° F.). 
         [0053]    Similarly, internal components  312  of the battery  200  can be made up of a combination of materials such as electrodes, separators and electrolyte (KOH). The internal components  312  can have mass density 0.00011646 lbf*s2/in/in3, thermal conductivity of 0.0326376 in*lbf/(s*in ° F.) in a perpendicular plane and 1.05784 in*lbf/(s*in ° F.) in plane and specific heat of 736,076 in*lbf/(lbf*s2/in ° F.). 
         [0054]    In some embodiments, the electrolyte  206  can be made up of free KOH having mass density 0.00013605 lbf*s2/in/in3, thermal conductivity of 0.00154 in*lbf/(s*in ° F.) and specific heat of 2,201,000 in*lbf/(lbf*s2/in ° F.). In an alternative embodiment, the electrolyte  206  can be made up of NaOH. Furthermore, some electrolytes may have additives such as ZnO or LiOH, for example. 
         [0055]    The silver tabs  208  (or wires) of the battery  200  can be made up of silver having mass density 0.000982 lbf*s2/in/in3, thermal conductivity of 52.33 in*lbf/(s*in ° F.) and specific heat of 201,500 in*lbf/(lbf*s2/in ° F.). 
         [0056]    Further, solder  314  of the battery  200  can be made up of materials, such as, but not restricted to tin (Sn) and lead (Pb). These materials can have mass density 0.000748, thermal conductivity of 6.384 in*lbf/(s*in ° F.) and specific heat of 154,483 in*lbf/(lbf*s2/in ° F.). In some embodiments, the percentage of tin in the solder  314  can be 60% and the percentage of lead in the solder  314  can be 40%. 
         [0057]    The terminals  204  of the battery  200  can be made up of copper, Ag plated steel, brass, tungsten, etc. having mass density 0.000818 lbf*s2/in/in3, thermal conductivity of 19.9 in*lbf/(s*in ° F.) and specific heat of 320,000 in*lbf/(lbf*s2/in ° F.). In an embodiment, some terminals can be crimped or welded. 
         [0058]    In addition, the thermal plastic  316  of the battery  200  can be made up of Polyphenylene Sulfide (PPS) material. The PPS can have mass density 0.0001682 lbf*s2/in/in3, thermal conductivity of 1.249 in*lbf/(s*in ° F.) and specific heat of 86,186 in*lbf/(lbfs2/in ° F.). 
         [0059]    In some embodiments, the thermal plastic  316  can be selected based on attributes, such as, but not restricted to, compatibility with electrolyte, conductivity of material, electrical resistivity of material, sealing cover to a case, modulus of elasticity (i.e. to restrain the battery  200  from swelling), compatibility with cleaning solvents, flexural strength, impact of strength, etc. 
         [0060]    Further, a base plate  318  of the battery  200  can be made up of copper. The base plate  318  can have mass density 0.000836 lbf*s2/in/in3, thermal conductivity of 50.0849 in*lbf/(s*in ° F.) and specific heat of 33,180 in*lbf/(lbf*s2/in ° F.). 
         [0061]      FIG. 4  is a table  400  illustrating an internal resistance R of the battery  200 , in accordance with disclosed subject matter. The internal resistance R can be calculated by performing a thermal test on the battery  200  at different time intervals. In some embodiments, the thermal test of a battery can be a cell discharge test. Embodiments are intended to include or otherwise cover any type of thermal test that may be beneficial to calculate internal resistance R of the battery. 
         [0062]    The internal resistance R of the battery  200  can be computed as a ratio of change in voltage (ΔV) and change in current (ΔI) in a time interval. 
         [0063]    In some embodiments, the internal resistance R of the battery  200  can be computed in a pause (PAU) state of the battery  200 . In alternate embodiments, the internal resistance R of the battery  200  can be computed in a discharge (DCH) state of the battery  200 . 
         [0064]    In an exemplary embodiment, an internal resistance R during discharging of the battery  200  at time 0.093 hour can be calculated. The internal resistance R during discharging of the battery  200  can be computed by dividing a change in voltage of the battery  200  from 1.69 volts to 1.75 volts with a change in current from 60.01 Amps to 30.00 Amps, and the internal resistance R is computed as 0.00220 Ohms. 
         [0065]    Further, in some embodiments, a percentage of Depth of Discharge (DOD) of the battery  200  can also be computed. The Depth of Discharge (DOD) can indicate a State of Charge (SOC) of the battery  200 . The DOD can determine a fraction of power that can be withdrawn from the battery  200 . For example, if DOD of a battery is set at 40% by a manufacturer then only 40% of the energy of the battery can be used by load such as electrical appliances, etc. In the above exemplary scenario, the DOD of the battery  200  can be computed as 0.6%. 
         [0066]    Similarly, during discharging state of the battery  200 , at time 2.045 hour and 2.046 hour, the internal resistance R of the battery  200  can be computed. The internal resistance R of the battery  200  can be computed by dividing a change in voltage from 1.50 volts at 2.045 hour to 1.53 volts at 2.046 hour with a change in current from 60.00 Amps at 2.045 hour to 30.01 Amps at 2.046 hour. Then, the internal resistance R is computed as 0.00100 Ohms. At this time, the DOD of the battery  200  can be computed as 26.5%. In furtherance the internal resistance R can be calculated during other periods of the discharge where the internal resistance can be computed from the change of voltage and current as referenced at 5.915 hour. The internal resistance R is computed as 0.00097. At this time the DOD of the battery can be 77.9%. 
         [0067]    It can be seen from the table  400  that as the time interval of the discharged battery state increases, the depth of discharge percentage also increases. 
         [0068]    Further, the thermal energy generated by the battery  200  can be calculated by h=Î2 R, wherein; h is heat generated by the battery  200 , I is the rate of discharge of the heat from the battery  200 , and R is the internal resistance of the battery  200 . 
         [0069]    Therefore, as the rate of heat discharge from the battery is increased, the thermal energy generated by the battery also increased. Therefore, rate of removing the heat discharge from the battery needs to be increased in order to remove the excess heat from the battery  200 . 
         [0070]      FIG. 5  is a table  500  illustrating heat generated at 100% DOD of the battery  200  having the case  202 , in accordance with disclosed subject matter. As shown in the table  500 , at each step, parameters such as current (in Amps) and duration (in minutes and seconds) are monitored. In some embodiments, power of the battery  200 , heat generation per cell, etc. can be computed based on the monitored parameters. 
         [0071]    At step 0, time duration is zero minutes, current is zero Amps, and the resistance in the battery  200  can be computed as 0.0022 Ohms. The power can be computed as zero Watts and therefore, the heat generated per cell can be zero lb-in/in3-sec. 
         [0072]    Similarly, at step 1, the current in the battery  200  is 60 Amps and time duration is 0.1 minute and 6 seconds, the internal resistance of the battery  200  can be computed as 0.0022 Ohms. Based on the monitored parameters, the power of the battery  200  can be computed as 7.92 Watts and, therefore, heat generated per cell can be 1.0014 lb-in/in3-sec. 
         [0073]    In some embodiments of the disclosed subject matter, total elapsed time can also be computed in seconds. In the table  500 , the total elapsed time between the step 0 and the step 1 can be computed as 6 seconds. 
         [0074]    Further, as time duration increases from 0.1 minute to 60 minutes at step 8, the internal resistance decreases to 0.001 Ohms and power generated is further reduced to 3.6 Watts, which is half of the heat generated at an initial time in the battery  200 . Therefore, the heat generated per cell in the battery  200  is reduced to 0.4552 lb-in/in3-sec. 
         [0075]      FIG. 6  is a graph illustrating heat generation when the battery  200  is 100% discharged, in accordance with the disclosed subject matter. 
         [0076]    In some embodiments, the heat generated by the battery  200  can be computed when current in the battery  200  is 60 Amps. The x-axis of the graph represents time in minutes and the y-axis of the graph represents the heat generated by the cells of the battery  200 . As the time increases from zero minutes to 150 minutes, the heat generated per cell of the battery  200  is constant to 1 lb-in/in3-sec. 
         [0077]    After 100 minutes, the heat generated per cell of the battery  200  can start decreasing with the increase in time. As can be seen from the table  600 , the heat generated per cell in the battery  200  at time 200 minutes is decreased to approximately 0.4 lb-in/in3-secs. 
         [0078]    Thereafter, the heat generated by the battery  200  can remain constant as the time increases after 200 minutes. This shows that the addition of the polyphenylene sulfide (PPS) into the mixture of the cell case  202  of the battery  200  can increase the thermal conductivity of the battery  200 , which further removes excess heat from the case  202  of the battery  200 . 
         [0079]    IV. Analysis Results 
         [0080]      FIGS. 7A-7F  illustrate finite element analysis results of the battery  200 , in accordance with disclosed subject matter. In some embodiments, the analysis for three-cells in a battery  200  in adiabatic environment (i.e. poor thermal conductivity) is shown. 
         [0081]      FIG. 7A  illustrates FEA analysis result of the battery cases of the related arts such as  100 A or  100 B in the adiabatic environment. The heat generated by the batteries as  100 A or  100 B is deposited near the center (e.g., cell cover  202 ) of the battery  200 . This can further result in an increase in temperature at the center of the cell case of the batteries  100 A and  100 B. The temperature near the center of the battery  100 A and  100 B can be increased to approximately 139° F. 
         [0082]      FIG. 7B  illustrates full model result of the three-cell FEA analysis, in accordance with disclosed subject matter. The results of the analysis can illustrate that excess heat from the cell case  202  of the battery  200  can be removed, which further reduces the temperature of the battery  200 . 
         [0083]    In some embodiments, the temperature of the cell cover  202  can be reduced to a range of 123° F. to 128° F. while the temperature at the cell edges  212  can be reduced to a range of 133° F. to 137° F. For example, referring to the table  500 , at step 7 and time duration 24000 sec, the maximum temperature of the case  202  of the battery  200  can be 140.665° F. and the minimum temperature of the case  202  of the battery  200  can be 123.506° F. Therefore, the heat generated by the battery  200  is less than 1 lb-in/in3-sec. 
         [0084]      FIG. 7C  illustrates three-cell FEA analysis of the battery  200  without the case  202  of the battery  200 , in accordance with disclosed subject matter. Each of the cells in the battery  200  can dissipate heat near the center of the case  202  of the battery  200 . Therefore, the maximum temperature near the center of the battery  200  at time 24000 sec can be as high as 140.665° F., while the minimum temperature near the center of the battery  200  at time 24000 sec can be as low as 136.969° F. 
         [0085]    Therefore, by using the case  202  made up of PPS can reduce the temperature near the center of the case  202  of the battery  200  by approximately 8° F. 
         [0086]      FIG. 7D  illustrates a heat transfer model of the battery  200 , in accordance with disclosed subject matter. In order to transfer heat from the case  202  of the battery  200 , a heat transfer model can be used. In some embodiments, the heat generated by the battery  200  can be transferred to a heat sink such as the heat sink  106 . In alternate embodiments, a thick conductive base plate  702  can be attached at the bottom of the battery  200 . In some embodiments, the conductive base plate can be a copper base plate. In alternate embodiments, the conductive base plate can be any metallic plate that can be used to remove heat from the battery  200 . In some embodiments, the thickness of the copper base plate  702  can be 0.125 inch. Embodiments are intended to include or otherwise cover any configuration of the copper base plate  702  to provide excess heat removal from the battery  200 . In fact, embodiments are intended to include or otherwise cover any configuration of the conductive plates that may be beneficial to provide excess heat removal from the battery  200 . 
         [0087]    In some embodiments, a thermal conductive plastic  704  can be added between the cells of the battery  200 . In certain embodiments, the thickness of the thermal conductive plastic  704  can be 0.250 inch. Embodiments are intended to include or otherwise cover any configuration of the thermal conductive plastic  704  to provide excess heat removal from the battery  200 . In fact, embodiments are intended to include or otherwise cover any configuration of the thermal conductive plastic that may be beneficial to provide excess heat removal from the battery  200 . 
         [0088]    Further, at the end faces of the case of the battery  200 , a thick thermal conductive plastic  706  can also be added. In some embodiments, the thickness of the thick thermal conductive plastic  706  can be 0.125 inch. Embodiments are intended to include or otherwise cover any configuration of the thick thermal conductive plastic  706  to provide excess heat removal from the battery  200 . In fact, embodiments are intended to include or otherwise cover any configuration of the thermal conductive plastic that may be beneficial to provide excess heat removal from the battery  200   
         [0089]    The addition of the copper base plate  702 , the thermal conductive plastic  704  and the thermal conductive plastic  706  can be used to remove excess heat from the battery  200  and therefore to increase thermal conductivity of the battery  200 . 
         [0090]      FIG. 7E  illustrates a result of the heat transfer model of the battery  200  shown in  FIG. 7D , in accordance with disclosed subject matter. The analysis shows a tremendous reduction in the temperature of the battery  200 . At time 24000 sec, the maximum temperature of the battery  200  is reduced to 132.8187° F., while the minimum temperature is also reduced to 114.808° F. Therefore, the temperature of the battery  200  may be reduced to approximately 8° F. that is less than the adiabatic condition that shows that the heat is transferred from the batteries  100 A and  100 B to the heat sink  106 . 
         [0091]      FIG. 7F  illustrates a cross sectional view of the three-cells in the battery  200 , in accordance with disclosed subject matter. The FEA analysis shows that the maximum temperature near the center of the battery  200  is now reduced to 132.8187° F. and the minimum temperature at the cell edges is reduced to 117.7655° F. The reduction in the temperature of the battery  200  improves thermal conductivity and therefore, improves life of the battery  200 . 
         [0092]    V. Alternative Embodiments 
         [0093]    While certain embodiments of the invention are described above, and  FIGS. 2-7  disclose the best mode for practicing the various inventive aspects, it should be understood that the invention can be embodied and configured in many different ways without departing from the spirit and scope of the invention. 
         [0094]    For example, embodiments are disclosed above in the context of three-cell battery. However, the disclosed cell case can be used in a battery having any number of cells to remove excess heat generated by the cells of the battery. 
         [0095]    The case of the battery can dispose any number of cells and further removes excess heat generated by each of the cells. However, embodiments are intended to cover the battery and its case that can include different regions having different number of cells. 
         [0096]    Exemplary embodiments are intended to include or otherwise cover any appropriate type of materials for manufacturing of a case of the battery disclosed above. 
         [0097]    Embodiments are disclosed above in the context of improving thermal conductivity of a case of a battery. However, embodiments are intended to cover methods and apparatus for removing excess heat generated by the cells of the battery. 
         [0098]    While the subject matter has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. All related art references discussed in the above Background section are hereby incorporated by reference in their entirety.