Patent Publication Number: US-2022238950-A1

Title: Traction battery having a battery cell array usable with different busbar modules and method of assembling such a traction battery

Description:
TECHNICAL FIELD 
     This disclosure relates generally to a traction battery and, more particularly, to a traction battery having a battery cell array usable with different busbar modules having different arrangements of busbars. 
     BACKGROUND 
     Electrified vehicles differ from conventional motor vehicles because electrified vehicles are selectively driven using one or more electric machines powered by a traction battery pack. The electric machines can drive the electrified vehicles instead of, or in addition to, an internal combustion engine. A traction battery pack of an electrified vehicle can include a plurality of arrays. Each array can include a plurality of individual battery cells. 
     With reference to prior art  FIGS. 7A-7C , to provide a “2P” array where the battery cell array is partitioned into groups of two individual battery cells connected in parallel, a first type of busbar module (BBM) is used with a first type of array. To provide a “3P” array where the battery cell array is partitioned into groups of three individual battery cells connected in parallel, a different, second type of BBM is used with a different, second type of array. To provide “4P” array where the battery cell array is partitioned into groups of four individual battery cells connected in parallel, a third type of BBM is used with a third type of battery cell array. Thus, in the prior art, to provide a 2P array, 3P array, 4P array, three different types of battery cell arrays are required along with three different types of busbar modules. 
     SUMMARY 
     A traction battery assembly according to an exemplary aspect of the present disclosure includes, among other things, a battery cell array having a plurality of individual battery cells. The battery cell array usable with a first busbar module having a first arrangement of busbars. The battery cell array is also usable with a second busbar module having a second arrangement of busbars. When the battery cell array is used with the first busbar module, the battery cell array is partitioned into a first number of groups of battery cells in parallel with each other. When the battery cell array is used with the second busbar module, the battery cell array is partitioned into a different, second number of groups of battery cells in parallel with each other. 
     In another exemplary embodiment of the foregoing assembly, each group within the first number of groups includes a first number of battery cells in parallel, and each group within the second number of groups includes a second, different number of battery cells in parallel. 
     In another exemplary embodiment of any of the foregoing assemblies, each group within the first number of groups includes two battery cells in parallel, and each group within the second number of groups includes three battery cells in parallel. 
     In another exemplary embodiment of any of the foregoing assemblies, the first and second busbar modules each include a housing and a plurality of busbars. 
     In another exemplary embodiment of any of the foregoing assemblies, each of the battery cells within the battery cell array includes a positive and a negative terminal. A positive terminal of a first one of the battery cells is directly adjacent a negative terminal of a second one of the battery cells within the battery cells array. The first one of the battery cells is directly adjacent the second one of the battery cells within the battery cell array. 
     In another exemplary embodiment of any of the foregoing assemblies, the battery cells are disposed along an axis. 
     In another exemplary embodiment of any of the foregoing assemblies, the battery cell is usable with the first busbar module and the second busbar module without changing an orientation of the battery cells relative to each other. 
     In another exemplary embodiment of any of the foregoing assemblies, the battery cells each include terminals that are each electrically connected to busbars of the first arrangement of busbars when the battery cell array is used with the first busbar module. 
     In another exemplary embodiment of any of the foregoing assemblies, the terminals are welded to busbars of the first arrangement of busbars to electrically connect the terminals to the busbars. 
     In another exemplary embodiment of any of the foregoing assemblies, the terminals are spring biased against busbars of the first arrangement of busbars to electrically connect the terminals to the busbars. 
     Another exemplary embodiment of any of the foregoing assemblies includes a third busbar module and a first poke-yoke configuration. The third busbar module is a different type of busbar module than the first and second busbar modules. The first poke-yoke configuration permits coupling the first or the second busbar modules of the first type to the battery cell array, and blocks coupling of the third busbar module to the battery cell array. 
     In another exemplary embodiment of any of the foregoing assemblies, the battery cell array is a first battery cell array that is a first type of battery cell array. The assembly further includes a second battery cell array of a second type that is different than the first type of battery cell array and a second poke-yoke configuration. The second poke-yoke configuration permits coupling the third busbar module to the second battery cell array, and blocks coupling of the first and second busbar modules to the battery cell array. 
     A traction battery connecting method according to another exemplary aspect of the present disclosure includes, among other things, using a battery cell array with a first busbar module having a first arrangement of busbars. The battery cell array is also usable with a second busbar module having a second arrangement of busbars. The battery cell array includes battery cells. When the battery cell array is used with the first busbar module, the battery cell array is partitioned into a first number of groups of battery cells in parallel. When the battery cell array is used with the second busbar module, the battery cell array is partitioned into a different, second number of groups of battery cell arrays in parallel. Each group within the first number of groups includes a first number of battery cells in parallel, and each group within the second number of groups includes a second, different number of battery cells in parallel. 
     In another exemplary embodiment of the foregoing method, each group within the first number of groups includes two battery cells in parallel, and each group within the second number of groups includes three battery cells in parallel. 
     In another exemplary embodiment of any of the foregoing methods, each of the battery cells within the plurality of battery cell array includes a positive and a negative terminal. A positive terminal of a first one of the battery cells is directly adjacent a negative terminal of a second one of the battery cells. The first one of the battery cells is directly adjacent the second one of the battery cells within the battery cell array. 
     In another exemplary embodiment of the foregoing method the battery cell is usable with the first busbar module and the second busbar module without changing an orientation of the battery cells relative to each other. 
     Another exemplary embodiment of any of the foregoing methods includes, when the battery cell array is used with the first arrangement of busbars, electrically connecting busbars of the first arrangement of busbars to terminals of the battery cells by welding the terminals of the battery cells to busbars of the first arrangement of busbars. 
     Another exemplary embodiment of any of the foregoing methods includes, when the battery cell array is used with the first arrangement of busbars, electrically connecting busbars of the first arrangement of busbars to terminals of the battery cells by spring-biasing the terminals of the battery cells to busbars of the first arrangement of busbars. 
     A traction battery assembly according to yet another exemplary aspect of the present disclosure includes, among other things, a first busbar module having a first arrangement of busbars, a second busbar module having a second arrangement of busbars, and a battery cell array including a plurality of battery cells that are selectively electrically connected in a configuration selected from a group consisting of a first configuration using the first busbar module and a different, second configuration using the second busbar module. 
     In another example of the foregoing assembly, when the plurality of battery cells are electrically connected in the first configuration, the battery cell array is partitioned into a first number of groups of battery cells in parallel with each other, when the plurality of battery cells are electrically connected in the second configuration, the battery cell assembly is partitioned into a different, second number of groups of battery cells in parallel with each other. 
     A traction battery assembly according to another example of the foregoing assembly includes a battery cell array having a plurality of battery cells. The battery cell array is usable with a first busbar module having a first arrangement of busbars, The battery cell array is usable with a second busbar module having a second arrangement of busbars. Each of the battery cells within the battery cell array includes a positive terminal and a negative terminal. A positive terminal of a first one of the battery cells within the battery cell array is directly adjacent a negative terminal of a second one of the battery cells. The first one of the battery cells is directly adjacent the second one of the battery cells within the battery cell array. 
     In another example of the foregoing assembly, when the battery cell array is used with the first busbar module, the battery cell array is partitioned into a first number of groups of battery cells in parallel with each other. When the battery cell array is used with the second busbar module, the battery cell array is partitioned into a different, second number of groups of battery cells in parallel with each other. 
     The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
         FIG. 1  illustrates a schematic view of an electrified vehicle powertrain. 
         FIG. 2  illustrates a perspective view of a battery assembly from a traction battery of the powertrain of  FIG. 1 . 
         FIG. 3 . illustrates selected portions of the battery assembly of  FIG. 2  and shows a top view of a battery cell array electrically connected to busbars of a first busbar module. 
         FIG. 4  illustrates the battery cell array of  FIG. 3  electrically connected to busbars of a different, second busbar module. 
         FIGS. 5A-5C  illustrate the battery cell array of  FIG. 3  electrically connected to different busbar modules to provide array variations having different numbers of individual battery cells connected in parallel. 
         FIGS. 6A and 6B  illustrate the battery cell array and selected busbar modules of  FIGS. 5A-5C , which are of a first type, and additionally illustrate a battery cell array and busbar modules of a second type. 
         FIGS. 7A-7C  illustrate prior art battery cell arrays electrically connected to prior art busbar modules to provide different numbers of individual battery cells connected in parallel. 
     
    
    
     DETAILED DESCRIPTION 
     A battery assembly for a traction battery can include a busbar module (BBM) having busbars that are electrically connected to battery cells within a battery cell array. This disclosure details a battery cell array that can be used with a first BBM or a second BBM. An arrangement of busbars within the first BBM is different than an arrangement of busbars within the second BBM. Changing the BBM used with the battery cell array is substantially all that is required to change the number of individual cells connected in parallel with one another within the battery cell array. 
     Referring to  FIG. 1 , a powertrain  10  of a plug-in hybrid electric vehicle (PHEV) includes a traction battery pack  14  having a plurality of battery assemblies  18 , an internal combustion engine  20 , a motor  22 , and a generator  24 . The motor  22  and the generator  24  are types of electric machines. The motor  22  and generator  24  may be separate or have the form of a combined motor-generator. 
     Although depicted as a PHEV, it should be understood that the concepts described herein are not limited to PHEVs and could extend to traction battery packs in any other type of electrified vehicle, including, but not limited to, other hybrid electric vehicles (HEVs), battery electric vehicles (BEVs), fuel cell vehicles, etc. 
     In this embodiment, the powertrain  10  is a power-split powertrain that employs a first drive system and a second drive system. The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels  28 . The first drive system includes a combination of the engine  20  and the generator  24 . The second drive system includes at least the motor  22 , the generator  24 , and the traction battery pack  14 . The motor  22  and the generator  24  are portions of an electric drive system of the powertrain  10 . 
     The engine  20  and the generator  24  can be connected through a power transfer unit  30 , such as a planetary gear set. Of course, other types of power transfer units, including other gear sets and transmissions, can be used to connect the engine  20  to the generator  24 . In one non-limiting embodiment, the power transfer unit  30  is a planetary gear set that includes a ring gear  32 , a sun gear  34 , and a carrier assembly  36 . 
     The generator  24  can be driven by the engine  20  through the power transfer unit  30  to convert kinetic energy to electrical energy. The generator  24  can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft  38  connected to the power transfer unit  30 . 
     The ring gear  32  of the power transfer unit  30  is connected to a shaft  40 , which is connected to the vehicle drive wheels  28  through a second power transfer unit  44 . The second power transfer unit  44  may include a gear set having a plurality of gears  46 . Other power transfer units could be used in other examples. 
     The gears  46  transfer torque from the engine  20  to a differential  48  to ultimately provide traction to the vehicle drive wheels  28 . The differential  48  may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels  28 . In this example, the second power transfer unit  44  is mechanically coupled to an axle  50  through the differential  48  to distribute torque to the vehicle drive wheels  28 . 
     The motor  22  can be selectively employed to drive the vehicle drive wheels  28  by outputting torque to a shaft  54  that is also connected to the second power transfer unit  44 . In this embodiment, the motor  22  and the generator  24  cooperate as part of a regenerative braking system in which both the motor  22  and the generator  24  can be employed as motors to output torque. For example, the motor  22  and the generator  24  can each output electrical power to recharge cells of the traction battery pack  14 . 
     With reference now to  FIG. 2 , the battery assemblies  18  of the traction battery pack  14  each include a battery cell array  60  and a busbar module  64 . The battery cell array  60  includes a plurality of individual battery cells  68 . The BBM  64  includes a first arrangement  72  of busbars and a busbar housing  76  that holds the first arrangement  72   
     The example battery cell array  60  includes twelve individual battery cells  68 , but other numbers of individual battery cells  68  could be used. The battery cells  68  are lithium ion cells in this example. In another example, the battery cells  68  could be pouch cells. 
     In the exemplary embodiment, the BBM  64  is positioned atop the battery cell array  60  to electrically connect the busbars of the first arrangement  72  to the battery cells  68 . The busbars of the first arrangement  72  can be directly connected to terminals  80  of the individual battery cells  68 . Welds, such as laser welds, can be utilized to secure the terminals  80  to the busbars of the first arrangement  72 . 
     Alternatively, the terminals  80  could be spring terminals that are biased against the busbars of the first arrangement  72  when the BBM  64  is secured relative to the battery cell array  60 . In such an example, when the BBM  64  is removed from the battery cell arrays  60 , the spring terminals spring back. The BBM  64  could snap fit to the battery cell array  60  to hold the BBM  64  relative to the battery cell arrays  60  in a position where the busbars of the first arrangement  72  are pressing against the spring terminals. A person having skill in this art and the benefit of this disclosure could understand spring terminals and how to bias spring terminals. 
     With reference to  FIG. 3 , the battery cell array  60  is shown connected to the first arrangement  72  of busbars of the BBM  64 . The battery cells  68  within the battery cell array  60  each include a positive “+” terminal  80  and a negative “−” terminal  80 . The battery cells  68  are disposed along an axis A such that a positive terminal  80  of a first one of the battery cells  68  is directly adjacent a negative terminal of a second one of the battery cells  68 . The first one of the battery cells  68  is directly adjacent the second one of the battery cells  68  within the battery cell array  60 . The polarities of the battery cells  68  thus alternate. 
     In the prior art, battery cells within a battery cell array have the positive terminals of the battery cells next to each other, and the negative terminals of the battery cells next to each other. Arranging the battery cells  68  within the battery cell array  60  such that the polarities alternate can facilitate use of the battery cell array  60  being used with BBMs having different arrangements of busbars. 
     The BBM  64  is configured such that, when the first arrangement  72  of busbars of the BBM  64  is connected to the terminals  80 , the battery cell array  60  is partitioned into six groups of individual battery cells. Each of the groups includes two individual battery cells  68  that are connected in parallel. 
     With reference to  FIG. 4 , the same battery cell array  60  can be used with a second different BBM  64 A, which has a second arrangement  72 A of busbars. When the busbars of the second arrangement  72 A are connected to the battery cells  68 , the battery cell array  60  is partitioned into four groups of three individual battery cells  68  connected in parallel. 
     The first arrangement  72  of busbars within the BBM  64  is different than the second arrangement  72 A of busbars within the BBM  64 . These differences enable the BBM  64  to partition the battery cell array  60  into groups of two individual battery cells  68  connected in parallel, and the BBM  64 A to partition the battery cell array  60  into groups of three individual battery cells  68  connected in parallel. 
       FIGS. 5A-5C , for example, shows the battery cell array  60  used with the BBM  64  to partition the battery cell array  60  into a 2P array, used with the BBM  64 A to partition the battery cell array  60 A into a 3P array, and used with a BBM  64 B to partition the battery cell array  60 B into a 4P array. The BBMs  64 ,  64 A,  64 B can include an identifier I such as a bar code such that, after the BBM is secured to the battery cell array  60 , the configuration of battery cells  68  (i.e., 2P, 3P, 4P) can be easily identified. The same battery cell array  60  can be used with BBM  64 ,  64 A, or  64 B to provide the desired partitioning of the battery cell array  60 . 
     With reference to  FIGS. 6A and 6B , the battery cell array  60  in the exemplary embodiment, is a first battery cell array  60  provided by a first manufacturer. A second battery cell array  60 ′ is provided by a different, second manufacturer. Electrical parameters and other characteristics of the first battery cell array  60  can be different than the electrical parameters and other characteristics of the second battery cell array  60 ′. For example, the first battery cell array  60  can have a first Amp-hour and the second battery pack  60 ′ can have a different, second Amp-hour rating. 
     In such examples, it may be desirable to connect the first battery pack  60  to one of the BBMs  64  or  64 A, but not other BBMs  64 ′ or  64 A′. The BBMs  64  or  64 A are a first type of BBM suitable for providing a 2P or 3P array with the battery cell array  60 , but not the battery cell array  60 ′. The BBMs  64 ′ or  64 A′ are a second type of BBM suitable for providing a 2P or 3P array with the battery cell array  60 ′, but not the battery cell array  60 . 
     First poke-yoke configurations  70  are incorporated into the battery cell array  60  and the BBM  64 , and into the battery cell array  60  and the BBM  64 A. The poke-yoke configurations  70  permit using the BBM  64  or the BBM  64 A with the battery cell array  60 , but block use of the BBM  64 ′ or the BBM  64 A′ with the battery cell array  60 . 
     Second poke-yoke configurations  70 ′ are incorporated into the battery cell array  60 ′ and the BBM  64 ′, and into the battery cell array  60 ′ and the BBM  64 A′. The poke-yoke configurations  70 ′ permit using the BBM  64 ′ or the BBM  64 A′ with the battery cell array  60 ′, but prevent using the BBM  64  or the BBM  64 A with the battery cell array  60 ′. 
     In this example, the first poke-yoke configurations  70  each include a slot and a tab. Of course, other poke-yoke configurations could be used in other examples. The tabs are on the BBM  64  and the BBM  64 A, and the slot is provided by the battery cell array  60 . The BBMs  64  and  64 A could each provide a slot and the battery cell array  60  could provide the tab. The slot and tab are positioned such that, when the BBM  64  or the BBM  64 A is used with the battery cell array  60 , the respective tab is received within the slot. 
     In this example, the second poke-yoke configurations  70 ′ also each include a slot and a tab. Again, other poke-yoke configurations could be used in other examples. The tabs are on the BBM  64 ′ and the BBM  64 A′, and the slot is provided by the battery cell array  60 ′. In another example, the BBMs  64 ′ and  64 A′ could each provide a slot and the battery cell array  60 ′ could provide the tab. The slot and tabs of the second poke-yoke configurations  70 ′ are positioned such that, when the BBM  64 ′ or the BBM  64 A′ is used with the battery cell array  60 ′, the respective tab is received within the slot. 
     Notably, the tabs and slots of the first poke-yoke configurations  70  are located in a different position than the second poke-yoke configurations  70 ′. Thus, the tab of the BBM  64 ′ could not be received within the slot of the battery cell array  60 . The poke-yoke configurations  70  and  70 ′ permit coupling of the BBM  64  or the BBM  64  to the battery cell array  60 , but block coupling of the BBM  64 ′ or the BBM  64 A′ to the battery cell array  60 . The poke-yoke configurations  70  and  70 ′ can thereby prevent incompatible combinations of BBMs and battery cell arrays. 
     The exemplary embodiment facilitates providing the battery cell array  60  as a commodity item that is mass produced without requiring significant customization for the number of battery cells  68  desired to be connected in parallel. The structural differences necessary to provide three individual battery cells  68  in parallel or two individual battery cells  68  in parallel can be substantially contained within the BBM  64  and the BBM  64 A. This approach can reduce complexity when compared to prior art designs that require a particular type of battery cell array if a 2P configuration were desired and another type of battery cell array if a 3P configuration were desired. 
     In the exemplary embodiments, one BBM is used with one battery cell array. In other examples, the BBM can span more than one battery cell array. For example, the battery cell array  60  could be placed adjacent another battery cell array. Both battery cell arrays are then electrically connected through a single BBM. 
     The variations are disclosed above in connection with 2P, 3P, or 4P configurations. Other configurations are certainly possible and fall within the scope of this disclosure. 5P configurations could be utilized, for example. 
     Features of the disclosed examples include a common battery cell array that can be utilized with a particular busbar module to provide the desired electrical connections. This can reduce overall complexity when multiple array variations are required. Keeping the battery cell array common across the variation can, among other things, reduce costs and development time. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.