Serviceable mid-pack collection rail
Patent Information
- Application Number
- DE102024111420
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-06-26
- Filing Date
- 2024-04-23
- Publication Date
- 2025-01-02
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
INTRODUCTIONElectric vehicles (EVs) may be operated with batteries that store energy that may be used to propel the vehicle. The batteries may include various components that facilitate energy storage and distribution.SUMMARYThe present solution provides a vehicle-serviceable bus bar that can be used to divide the voltage of a battery pack (e.g., into two halves of about 50% of the battery pack voltage), enabling convenient vehicle service, maintenance, and repair at a reduced voltage level. The bus bar may allow a service technician to disconnect the high voltage within a battery pack from the rest of the vehicle without removing the battery pack from the vehicle. The bus bar may also allow for disconnection of a battery pack from the high voltage distribution box of the EV or from another battery pack to allow for maintenance of one of the battery packs inside or outside the vehicle, as well as to allow inter-compatible battery packs to be used in the same vehicle. The bus bar may include a first bus bar electrically coupled to a first portion of the battery pack (e.g., or to a first battery pack) and a second bus bar to be coupled to a second portion of the battery pack (e.g., or to a second battery pack). Each of the first and second busbars may include respective first and second bridges bent (e.g., bent downward at an angle of 90%) relative to a body of each of the respective first and second busbars. A connector bridge may be used to electrically couple the first and second bridges. To disconnect the bus bar, the connecting bridge may be removed, decoupling the first and second bridges and electrically disconnecting the first portion of the battery pack (or the first battery pack) from the second portion of the battery pack (or the second battery pack). A cover made of electrically insulating material may be used to insulate, shield, or cover the connector bridge, the first and second bridges, and the bodies of the first and second bus bars.At least one aspect is directed to a system. The system may include a bus bar for electrically coupling to a battery pack between two groups of battery cells of the battery pack. The bus bar may be disposed at an opening of the housing of the battery pack. The bus bar may be exposed by an access cover.At least one aspect is directed to a method for electrically decoupling at least a portion of a battery pack. The method may include electrically coupling a bus bar to two groups of battery cells of a battery pack. The method may include disposing the bus bar at an opening of a housing of the battery pack. The method may include exposing the bus bar for access by an access cover.At least one aspect is directed to a battery system of an electric vehicle. The battery system may include a bus bar for electrically coupling to a battery pack between two groups of battery cells of the battery pack. The bus bar may be disposed at an opening of the housing of the battery pack. The bus bar may be exposed by an access cover. The battery system may include a bridge connector for electrically coupling a first body of the bus bar to the second body of the bus bar, the bridge connector being removable via the access cover on an end plate of the housing to electrically decouple a first group of the two groups of battery cells electrically coupled to the first body from a second group of the two groups of battery cells electrically coupled to the second body.These and other aspects and implementations are discussed in detail below. The above information and the following detailed description include illustrative examples of various aspects and implementations, and provide an overview or framework for understanding the nature and character of the claimed aspects and implementations.The drawings provide an illustrative representation and further understanding of the various aspects and implementations, and are part of this specification. The above information and the following detailed descriptions and drawings include illustrative examples and should not be considered as limiting.BRIEF DESCRIPTION OF THE DRAWINGSThe accompanying drawings are not to scale. Like numerals and labels in the various drawings identify like elements. For clarity, not every component needs to be labeled in each drawing. The following are shown: FIG. 1 illustrates an example electric vehicle. FIG. 2A illustrates an example of a battery pack. FIG. 2B illustrates an example of a battery pack with battery subassemblies. FIG. 2C illustrates a cross-sectional view of a battery cell. FIG. 2D illustrates a cross-sectional view of a battery cell. FIG. 2E illustrates a cross-sectional view of a battery cell. FIG. 3 illustrates an example of a battery system that includes an access cover for accessing a bus bar of the battery pack. FIG. 4 illustrates an example of a battery system having a bus bar for reducing the voltage of a battery pack. FIG. 5 illustrates an example of a cross-sectional view of a bus bar for reducing the voltage of the battery system. FIG. 6 illustrates an example of an access opening for accessing the bus bar to reduce the voltage of a battery pack. FIG. 7 illustrates an example of a plan view of the access opening and the bus bar in a battery pack. FIG. 8 illustrates a flowchart of an example method for electrically decoupling at least a portion of a battery pack using a bus bar.DETAILED DESCRIPTIONDetailed descriptions of various concepts related to and implementations of methods, apparatus, and systems for electrically decoupling at least a portion of a battery pack using a bus bar follow. The concepts introduced above and discussed in detail below may be implemented in numerous ways.This disclosure is generally directed to a system that includes a vehicle serviceable bus bar of a battery pack. The bus bar may be positioned in a center portion, an intermediate node, or a center of a battery pack (e.g., a battery pack subassembly) and divide the voltage of the battery pack by about 50% (e.g., between two groups of battery cells). For example, the bus bar 310 may be deployed from an electrical architecture perspective and connected to battery cells 120 of the battery pack 110 such that it provides serviceability by, for example, bisecting the voltage of the battery pack 110 at the mid-pack (e.g., providing two halves of the voltage of the pack). The bus bar allows convenient maintenance, maintenance, and repair of the battery pack and any associated components in the vehicle. For example, the system described herein enables disconnecting the high voltage within the battery pack from the rest of the vehicle from outside the battery pack while the battery pack remains within the vehicle. Accordingly, a service technician may service and replace components within the battery pack and separately from the rest of the vehicle while the battery pack remains within the vehicle. Moreover, one battery pack may include two battery packs: one that is serviceable when it is outside the vehicle and another that is serviceable when it remains inside the vehicle, the system described herein allowing the bus bar to be disconnected while both packs are inside the vehicle, whereby inter-compatible battery packs may be used in the same vehicle.The bus bar connects the battery pack (e.g., the battery cells therein) to the various components such as a high voltage distribution box (HVDB), fuses, current sensors, contactors, battery management system (BMS), battery voltage temperature monitor (BVT), and BVT monitor, respectively, and so forth. The bus bar may be electrically coupled to a current collector assembly (CCA) bus bar that is connected to the terminals of the battery cells. Such components can be maintained, maintained, checked, monitored or evaluated after the busbar has been disconnected in the manner described. For example, after disconnection of the bus bar, the voltage at the HVDB is 0 V, and the current detected by the current sensors is 0 Ampere.The bus bar may include a first bus bar coupled to a first portion of the battery pack and a second bus bar coupled to a second portion of the battery pack. Each of the first and second bus bars includes respective first and second bridges bent (e.g., bent downward at an angle of 90%, and so forth) relative to a body of each of the respective first and second bus bars. The bus bar may include a connecting bridge to couple the first and second bridges. To disconnect the bus bar (e.g., to electrically decouple the high voltage within the battery pack from the high voltage distribution box), the connecting bridge may be removed, decoupling the first and second bridges. A cover made of insulating material (e.g., plastic material) may be provided to cover the bodies of the first and second bus bars. In one aspect, the present solution may include a bus bar that may be maintained from outside the battery pack, which may be configured as a modular accessory for the module or sub-assembly within the battery pack. This may allow, for example, two variations of a battery pack to be manufactured with the same module or subassembly. One variation may include the serviceable bus bar subassembly and thus allow service accessible via the bus bar while the battery pack remains within the vehicle, while another battery pack variation may not include, for example, this subassembly. The variant of the pack may then be selected based on the configuration of the vehicle. The present solution may be directed to the 'mid-pack' electrical architecture where the bus bar at an intermediate node of the battery pack may provide a serviceable feature to reduce the voltage of the battery pack such that the maximum voltage present in the system is reduced to facilitate serviceability.FIG. 1 illustrates an example cross-sectional view 100 of an electric vehicle 105 in which at least one battery pack 110 is installed. Electric vehicles 105 may include, but are not limited to, electric trucks, sport utility vehicles (SUVs), electric vans, electric automobiles, electric cars, electric bicycles, electric scooters, electric cars, electric cars or commercial vehicles, hybrid vehicles or other vehicles such as marine or air transport vehicles, aircrafts, helicopters, submarines, boats, or drones. The battery pack 110 may also be used as an energy storage system for powering a building, such as a residential building or business buildings. Electric vehicles 105 may be fully electric or partially electric (e.g., plug-in hybrid), and further electric vehicles 105 may be fully autonomous, partially autonomous, or unmanned. Electric vehicles 105 may also be human-operated or non-autonomous. Electric vehicles 105, such as electric trucks or cars, may include on-board battery packs 110, batteries 115 or battery subassemblies 115, or battery cells 120 for powering the electric vehicles. The electric vehicle 105 may include a chassis 125 (e.g., a frame, an internal frame, or a support structure). The chassis 125 may support various components of the electric vehicle 105. The chassis 125 may extend over a front portion 130 (e.g., a hood portion), a body portion 135, and a rear portion 140 (e.g., a trunk, payload, or trunk portion) of the electric vehicle 105. The battery pack 110 may be installed or placed in the electric vehicle 105. For example, the battery pack 110 may be installed on the chassis 125 of the electric vehicle 105 in one or more of the front portion 130, the body portion 135, and the rear portion 140. The battery pack 110 may include or be connected to at least one bus bar, e.g., a current collector element. For example, the first bus bar 145 and the second bus bar 150 may include electrically conductive material to connect or otherwise electrically couple the battery 115, the battery subassemblies 115, or the battery cells 120 to other electrical components of the electric vehicle 105 to provide electrical power to various systems or components of the electric vehicle 105.FIG. 2A illustrates an example battery pack 110. Referring to FIG. 2A, the battery pack 110 may provide power to the electric vehicle 105, among other things. Battery packs 110 may include any arrangement or network of electrical, electronic, mechanical, or electromechanical devices to power a vehicle of any type, such as electric vehicle 105. The battery pack 110 may include at least one housing 205. The housing 205 may include at least one battery subassembly 115 or at least one battery cell 120, as well as other battery pack components. The battery subassembly 115 may be or include one or more groups of prismatic cells, cylindrical cells, pouch cells, or other form factors of the battery cells 120. The housing 205 may include a shield at the bottom of the battery subassembly 115 to protect the battery subassembly 115 and / or cells 120 from external influences, for example, when the electric vehicle 105 is controlled over rough terrain (e.g., terrain, trenches, rocks, etc.). The battery pack 110 may include at least one cooling line 210 that may distribute liquid through the battery pack 110 as part of a heat / temperature control or heat exchange system, which may also include at least one thermal component (e.g., cooling plate) 215. The thermal component 215 may be positioned relative to an upper sub-module and a lower sub-module such that it is located between, among other things, the upper and lower sub-modules. The battery pack 110 may include any number of thermal components 215. For example, one or more thermal components 215 may be present per battery pack 110 or per battery subassembly 115. At least one cooling line 210 may be coupled to, part of, or independent of the thermal component 215.FIG. 2B illustrates example battery subassemblies 115, and FIGS. 2C, 2D, and 2E illustrate an example cross-sectional view of a battery cell 120. The battery subassembly 115 may include at least one sub-module. For example, the battery subassembly 115 may include at least one first (e.g., upper) sub-module 220 or at least one second (e.g., lower) sub-module 225. At least one thermal component 215 may be disposed between the upper sub-module 220 and the lower sub-module 225. For example, a thermal component 215 may be configured for heat exchange with a battery subassembly 115. The thermal component 215 may be disposed or thermally coupled between the upper sub-module 220 and the lower sub-module 225. A thermal thermal thermal energy.Component 215 may also be thermally coupled to more than one battery sub-assembly 115 (or more than two sub-modules 220, 225). The thermal components 215 shown adjacent to each other may be combined into a single thermal component 215 spanning the size of one or more sub-modules 220 or 225. The thermal component 215 may be positioned below the sub-module 220 and above the sub-module 225, between the sub-modules 220 and 225, on one or more sides of the sub-modules 220, 225, among other things. The thermal component 215 may be disposed in sidewalls, cross members, structural beams, and various other components of the battery pack, as in the battery pack 110 described above. The battery submodules 220, 225 may together form a battery subassembly 115. In some examples, each sub-module 220, 225 may be considered a complete battery sub-module 115 rather than a sub-module.The battery subassemblies 115 may each include a plurality of battery cells 120. The battery subassemblies 115 may be disposed within the housing 205 of the battery pack 110. The battery subassemblies 115 may include battery cells 120, which may be cylindrical cells or prismatic cells, for example. The battery subassembly 115 may operate as a modular unit of battery cells 120. For example, a battery sub-assemblies 115 may collect current or electrical power from the battery cells 120 included in the battery sub-assemblies 115 and provide the current or electrical power as output of the battery pack 110. The battery pack 110 may include any number of battery subassemblies 115. For example, the battery pack may include one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or other number of battery subassemblies 115 disposed within the housing 205. It should also be appreciated that each battery sub-assembly 115 may include an upper sub-module 220 and a lower sub-module 225, possibly with a thermal component 215 between the upper sub-module 220 and the lower sub-module 225. The battery pack 110 may include or define a plurality of areas in which the battery subassembly 115 or the battery cells 120 may be positioned. The battery subassemblies 115 may be square, rectangular, round, triangular, symmetrical, or asymmetrical. In some examples, the battery subassemblies 115 may have different shapes such that some battery subassemblies 115 are rectangular and other battery subassemblies 115 are square, among other possibilities. The battery subassembly 115 may include or define a plurality of slots, holders, or containers for a plurality of battery cells 120. It should be understood that the representations and descriptions illustrated herein are provided by way of example only and are not to be considered limiting. For example, the battery cells 120 may be inserted into the battery pack 110 without the battery sub-modules 220 and 225. The battery cells 120 may be arranged in the battery pack 110 in a cell-to-pack configuration without the sub-modules 220 and 225, among other things.Battery cells 120 have a variety of form factors, shapes, or sizes. For example, the battery cells 120 may have a cylindrical, rectangular, square, cubic, flat, pouch, elongated, or prismatic shape factor. For example, as shown in FIG. 2C, the battery cell 120 may be cylindrical. For example, as shown in FIG. 2D, the battery cell 120 may be prismatic. For example, as shown in FIG. 2E, the battery cell 120 may include a pouch form factor. The battery cells 120 may be arranged by, for example, inserting a wound or stacked electrode roll (e.g., a jelly roll) including an electrolyte material into at least one battery cell housing 230. The electrolyte material, e.g., an electrically conductive fluid or other material, may aid electrochemical reactions at the electrodes to generate, store, or provide electrical power to the battery cell by allowing conduction of ions between a positive and a negative electrode. The battery cell 120 may include an electrolyte layer, wherein the electrolyte layer may be or may include a solid electrolyte material capable of conducting ions. For example, the solid electrolyte layer may conduct ions without receiving a separate liquid electrolyte material. The electrolyte material, e.g., an electrically conductive fluid or other material, may aid in ionic conduction between the electrodes to generate or provide electrical power to the battery cell 120. The housing 230 may have various shapes including, for example, cylindrical or rectangular. Electrical connections may be made between the electrolyte material and the components of the battery cell 120. For example, electrical connections to the electrodes may be formed with at least a portion of the electrolyte material at two points or regions of the battery cell 120, for example to form a first polarity terminal 235 (e.g., a positive pole or anode terminal) and a second polarity terminal 240 (e.g., a negative pole or cathode terminal). The polarity terminals may be made of electrically conductive material to conduct electrical current from the battery cell 120 to an electrical load, such as a component or system of the electric vehicle 105.For example, the battery cell 120 may include at least one lithium-ion battery cell. In lithium ion battery cells, lithium ions may be transferred between positive and negative electrodes during charging and discharging of the battery cell. For example, the battery cell anode may include lithium or graphite, and the battery cell cathode may include a lithium-based oxide material. The electrolyte material may be disposed in the battery cell 120 to separate the anode and cathode from each other and facilitate transfer of lithium ions between the anode and cathode. Note that the battery cell 120 may also be formed in the form of an all-solid-state battery cell using solid electrodes and solid electrolytes. Solid electrodes or electrolytes may be or include inorganic solid electrolyte materials (e.g., oxides, sulfides, phosphides, ceramics), solid polymer electrolyte materials, hybrid solid electrolytes, or combinations thereof. In some embodiments, the solid electrolyte layer may include polyanionic or oxide-based electrolyte material (e.g., lithium super-ionic conductors (LISICONs), sodium super-ionic conductors (NASICONs), perovskites having the formula ABO3(A=Li, Ca, Sr, La, and B=Al, Ti), garnet type having the formula A 3 B 2( XO 4)3( A=Ca, Sr, Ba, and X=Nb, Ta), lithium phosphorus oxy-nitride (Li x PO y N z). In some embodiments, the solid electrolyte layer may include a glassy, ceramic, and / or sulfide-based crystalline electrolyte (e.g., Li 3 PS 4, Li 7 P 3 S 11, Li 2 S-P 2 S 5, Li 2 S-B 2 S3, SnS-P2S5, Li2S-SiS2, Li 2 S-P 2 S 5, Li 2 S-GeS 2, Li 10 GeP 2 S 12) and / or sulfide-based lithium argyrods of the formula Li 6 PS 5 X (X=Cl, Br) such as Li6PS5Cl). Moreover, solid polymer electrolyte materials may include a polymer electrolyte material (e.g., a hybrid or pseudo solid state electrolyte), e.g., polyacrylonitrile (PAN), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF), among others.The battery cell 120 may be included in the battery subassemblies 115 or battery packs 110 to power components of the electric vehicle 105. The battery cell housing 230 may be disposed in the battery subassembly 115, the battery pack 110, or a battery array installed in the electric vehicle 105. The housing 230 may have any shape, such as cylindrical with a circular (e.g., as shown in FIG. 2C, among others), elliptical, or ovular base, to name a few. The shape of the housing 230 may also be prismatic with a polygonal base, among other things, as shown in FIG. 2D. As shown in FIG. 2E, the housing 230 may include, among other things, a pouch form factor. The housing 230 may include other shape factors such as, but not limited to, a triangle, a square, a rectangle, a pentagonal, and a hexagon. In some embodiments, the battery pack may not include battery subassemblies (e.g., subassembly-free). For example, the battery pack may have a "subassembly-free" or "cell-to-pack" i configuration, where the battery cells are directly arranged in a battery pack without arrangement in a subassembly.The housing 230 of the battery cell 120 may include one or more materials having different electrical conductivity or thermal conductivity, or a combination thereof. The electrically conductive and thermally conductive material for the housing 230 of the battery cell 120 may include a metallic material such as, but not limited to, aluminum, an aluminum alloy including copper, silicon, tin, magnesium, manganese, or zinc (e.g., 1000, 4000, or 5000 series aluminum), iron, an iron-carbon alloy (e.g., steel), silver, nickel, copper, and a copper alloy. The electrically insulating and thermally conductive material for the housing 230 of the battery cell 120 may include, but is not limited to, a ceramic material (e.g., and without limitation, silicon nitride, silicon carbide, titanium carbide, zirconium dioxide, beryllium oxide), and a thermoplastic material (e.g., polyethylene, polypropylene, polystyrene, polyvinyl chloride, or nylon). In examples where the housing 230 of the battery cell 120 is prismatic (e.g., as shown in FIG. 2D, among others) or cylindrical (e.g., as shown in FIG. 2C, among others), the housing 230 may include a rigid or semi-rigid material such that the housing 230 is rigid or semi-rigid (e.g., cannot be easily deformed or manipulated into another shape or form factor). In examples where the housing 230 includes a pouch form factor (e.g., as shown in FIG. 2E, among other things), the housing 230 may include a flexible, deformable, or non-rigid material such that the housing 230 may be bent, deformed, or manipulated into another form factor or shape.The battery cell 120 may include at least one anode layer 245 that may be disposed in the cavity 250 defined by the housing 230. The anode layer 245 may include a first redox potential. The anode layer 245 may draw electrical current into the battery cell 120 and emit electrons during operation of the battery cell 120 (e.g., charging or discharging of the battery cell 120). The anode layer 245 may include an active substance. The active substance may include, for example, activated carbon or a material permeated with conductive materials (e.g., artificial or natural graphite or a mixture thereof), lithium titanate (Li 4 Ti 5 O 12) or a silicon-based material (e.g., silicon metal, oxide, carbide, prelithiated), or other lithium alloy anodes (Li-Mg, Li-Al, Li-Ag alloy, etc.), or composite anodes consisting of lithium and carbon, silicon and carbon, or other compounds. The active substance may include graphitic carbon (e.g., ordered or disordered carbon with sp 2- hybridization), a Li metal anode or a silicon-based carbon composite anode, or other lithium alloy anodes (Li-Mg, Li-Al, Li-Ag alloy, etc.) or lithium and carbon composite anodes, silicon and carbon, or other compounds. In some examples, an anode material may be formed within a current collector material. For example, an electrode may include a current collector (e.g., copper foil) having an anode formed in situ (e.g., Li metal) on a surface of the current collector facing the separator or the solid electrolyte. In such examples, the composite cell does not comprise an anode active material in an uncharged state.The battery cell 120 may include at least one cathode layer 255 (e.g., a composite cathode layer, a connection cathode layer, a connection cathode, a composite cathode, or a cathode). The cathode layer 255 may include a second redox potential that may be different than the first redox potential of the anode layer 245. The cathode layer 255 may be disposed in the cavity 250. The cathode layer 255 may emit electrical current from the battery cell 120 and may receive electrons during discharge of the battery cell 120. The cathode layer 255 may also accept lithium ions during discharge of the battery cell 120. Conversely, the cathode layer 255 may draw electrical current into the battery cell 120 and may emit electrodes during charging of the battery cell 120. The cathode layer 255 may release lithium ions during charging of the battery cell 120.The battery cell 120 may include a layer 260 disposed in the cavity 250. The layer 260 may include a solid electrolyte layer. The layer 260 may include a separator that is wetted by a liquid electrolyte. The layer 260 may include a polymeric material. The layer 260 may include a polymer separator. The layer 260 may be disposed between the anode layer 245 and the cathode layer 255 to separate the anode layer 245 and the cathode layer 255. The polymer separator may physically separate the anode and the cathode from a cell short. A separator can be wetted with a liquid electrolyte. The liquid electrolyte may be diffused into the anode layer 245. The liquid electrolyte may be diffused into the cathode layer 255. The layer 260 may help transfer ions (e.g., Li +- ions) between the anode layer 245 and the cathode layer 255. Layer 260 may transfer Li +- cations from anode layer 245 to cathode layer 255 during the discharge process of battery cell 120. Layer 260 may transfer lithium ions from cathode layer 255 to anode layer 245 during the charging process of battery cell 120.The redox potential of layers (e.g., the first redox potential of the anode layer 245 or the second redox potential of the cathode layer 255) may vary based on a chemistry of the respective layer or a chemistry of the battery cell 120. For example, lithium ion batteries may include an LFP (lithium iron phosphate) chemistry, an LMFP (lithium manganese iron phosphate) chemistry, an NMC (Nickelmangancobalt) chemistry, an NCA (nickel cobalt aluminum) chemistry, an OLO (over-lithiated oxide) chemistry, or an LCO (lithium cobalt oxide) chemistry for a cathode layer (e.g., the cathode layer 255). Lithium ion batteries may include graphite chemistry, silicon graphite chemistry, or lithium metal chemistry for the anode layer (e.g., anode layer 245).For example, lithium ion batteries may include olivine phosphate (LiMPO 4, M=Fe and / or Co and / or Mn and / or Ni)), LISICON or NASICON phosphates (Li 3 M 2( PO 4)3 and LiMPO 4 O x, M=Ti, V, Mn, Cr and Zr), for example lithium iron phosphate (LFP), lithium iron manganese phosphate (LMFP), examples of layered oxides (LiMO 2, m=Ni and / or Co and / or Mn and / or Fe and / or Al and / or Mg), NMC chemistry (Nickelmangancobalt ), NCA chemistry (nickel cobalt aluminum) or LCO chemistry (lithium cobalt oxide) for a cathode layer, lithium-rich layer oxides (Li 1+x M 1-x O 2) ( Ni and / or Mn and / or Co), (OLO or LMR), Examples of the spinel include spinel (LiMn 2 O 4) and high voltage spinel (LiMn 1,5 Ni 0,5 O 4), disordered rock salt, fluorophosphates Li 2 FePO 4 F (M=Fe, Co, Ni), and fluorosulfates LiMSO 4 F (M=Co, Ni, Mn) (e.g., the cathode layer 255). Lithium ion batteries may include graphite chemistry, silicon graphite chemistry, or lithium metal chemistry for the anode layer (e.g., anode layer 245). For example, a cathode layer with LFP chemistry may have a redox potential of 3.4 V versus Li / Li + while an anode layer with graphite chemistry may have a redox potential of 0.2 V versus Li / Li +.Electrode layers may include anode active material or cathode active material, usually in addition to a conductive carbon material, a binder, additives other than a coating on a current collector (metal foil). The chemical composition of the electrode layers may affect the redox potential of the electrode layers. For example, cathode layers (e.g., cathode layer 255) may include medium to high nickel (50-80% or equal to 80% Ni) lithium transition metal oxide, such as a particulate Lithiumnickelmangancobaltoxid ("LiNMC"), a lithium nickel cobalt aluminum oxide ("LiNCA"), a Lithiumnickelmangancobaltaluminiumoxid ("LiNMCA"), or lithium metal phosphates, such as lithium iron phosphate ("LFP") and lithium iron manganese phosphate ("LMFP"). Anode layers (e.g., anode layer 245) may include conductive carbon materials such as graphite, carbon black, carbon nanotubes, and the like. Anode layers may include, for example, Super P carbon black, Ketjen black, acetylene black, SWCNT, MWCNT, graphite, carbon nano-fiber, or graphene.Electrode layers may also include chemical bond materials (e.g., binders). Binders may include polymeric materials such as polyvinylidene fluoride ("PVDF"), polyvinylpyrrolidone ("PVP"), styrene butadiene or styrene butadiene rubber ("SBR"), polytetrafluoroethylene ("PTFE"), or carboxymethylcellulose ("CMC"). Binder materials may include: agar agar, alginate, amylose, gum arabic, carrageenan, casein, chitosan, cyclodextrins (carbonyl beta), ethylene propylene diene monomer (EPDM) gum, gelatin, gellan gum, guar gum, karaya gum, cellulose (natural), pectin, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS), polyacrylic acid (PAA), poly(methyl acrylate) (PMA), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), polyacrylonitrile (PAN), polyisoprene (PIpr), polyaniline (PANi), polyethylene (PE), polyimide (PI), Polystyrene (PS), polyurethane (PU), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), starch, styrene butadiene rubber (SBR), tara gum, tragacanth gum, fluoroacrylate (TRD202A), xanthan gum, or mixtures of any two or more thereof.Current collector materials (e.g., a current collector foil to which an electrode active material is laminated to form a cathode layer or an anode layer) may include a metal material. For example, current collector materials may include aluminum, copper, nickel, titanium, stainless steel, or carbonaceous materials. The current collector material may be formed as a metal foil. For example, the current collector material may be an aluminum (Al) or copper (Cu) foil. The current collector material may be a metal alloy made of Al, Cu, Ni, Fe, Ti, or a combination thereof. The current collector material may be a metal foil coated with a carbon material, such as carbon coated aluminum foil, carbon coated copper foil, or other carbon coated foil material.The layer 260 may include or be made from a liquid electrolyte material. For example, layer 260 may be or include at least one layer of polymeric material (e.g., polypropylene, polyethylene, or other material), including pores that are wetted with (e.g., saturated with, saturated with, filled with, or receiving) a liquid electrolyte substance to allow ions to move between the electrodes. The liquid electrolyte material may include a lithium salt dissolved in a solvent. The lithium salt for the liquid electrolyte material for layer 260 may include, for example, lithium tetrafluoroborate (LiF 4), lithium hexafluorophosphate (LiPF 6) and lithium perchlorate (LiClO 4) among others. The solvent may include, for example, dimethyl carbonate (DMC), ethylene carbonate (EC), and diethyl carbonate (DEC), among others. The liquid electrolyte is not necessarily arranged in the vicinity of the layer 260, but the liquid electrolyte can fill the battery cells 120 in different ways. The layer 260 may include or be made from a solid electrolyte material, such as, but not limited to, a ceramic electrolyte material, polymer electrolyte material, or a glassy electrolyte material, or any combination thereof.In some embodiments, the solid electrolyte film may include at least one layer of a solid electrolyte. Solid electrolyte materials of the solid electrolyte layer may include inorganic solid electrolyte materials (e.g., oxides, sulfides, phosphides, ceramics), polymer solid electrolyte materials, hybrid solid electrolytes, or combinations thereof. In some embodiments, the solid electrolyte layer may include polyanionic or oxide-based electrolyte material (e.g., lithium super-ionic conductors (LISICONs), sodium super-ionic conductors (NASICONs), perovskites having the formula ABO3(A=Li, Ca, Sr, La, and B=Al, Ti), garnet type having the formula A 3 B 2( XO 4)3( A=Ca, Sr, Ba, and X=Nb, Ta), lithium phosphorus oxy-nitride (Li x PO y N z). In some embodiments, the solid electrolyte layer may include a glassy, ceramic, and / or sulfide-based crystalline electrolyte (e.g., Li 3 PS 4, Li 7 P 3 S 11, Li 2 S-P 2 S 5, Li 2 S-B 2 S3, SnS-P2S5, Li2S-SiS2, Li 2 S-P 2 S 5, Li 2 S-GeS 2, Li 10 GeP 2 S 12) and / or sulfide-based lithium argyrods of the formula Li 6 PS 5 X (X=Cl, Br) such as Li6PS5Cl). Moreover, solid polymer electrolyte materials may include a polymer electrolyte material (e.g., a hybrid or pseudo solid state electrolyte), e.g., polyacrylonitrile (PAN), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF), among others.In examples where layer 260 includes a liquid electrolyte material, layer 260 may include a non-aqueous polar solvent. The non-aqueous polar solvent may include a carbonate such as ethylene carbonate, propylene carbonate, diethyl carbonate, ethylmethyl carbonate, dimethyl carbonate, or a mixture of any two or more thereof. The layer 260 may include at least one additive. The additives may include vinylidene carbonate, fluoroethylene carbonate, ethyl propionate, methyl propionate, methyl acetate, ethyl acetate, or a mixture of any two or more thereof. The layer 260 may include a lithium salt material. The lithium salt may be lithium perchlorate, lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluorosulfonyl)imide, or a mixture of any two or more thereof. The lithium salt may be present in layer 260 from greater than 0 M to about 1.5 M. Once disposed in the battery cell 120, the liquid electrolyte may be present and contact the battery subcomponents present in the battery cell 120. The battery subcomponents may include the cathode, anode, separator, current collector, etc.FIG. 3 illustrates an example block diagram of an example battery system 300, also referred to as system 300, having a battery pack 110 that includes an access cover 340 for accessing a bus bar 310 for reducing battery pack voltage. The battery system 300 may include one or more battery packs 110. Each battery pack 110 may include a housing 344. The battery pack 110 may include one or more battery subassemblies 115. Each of the battery subassemblies 115 may include one or more cells 120. In some embodiments, a battery pack 110 may include a plurality (e.g., a group) of battery cells 120.The battery pack 110 may include an access cover 340. The access cover 340 may include any access element or component that protects or exposes access to the bus bar 310. The access cover 340 may be a portion of the end plate 342, which may be a portion of the housing 344. The access cover 340 may provide access to the bus bar 310 enclosed under (e.g., on the other side) the access cover 340 for maintenance or inspection. The access cover 340 may include an electrically insulating material (e.g., a plastic) to protect the bus bar 310 within the battery pack 110 from environmental elements such as dust or moisture. The access cover 340 may allow a user (e.g., a maintenance technician or mechanic) to access the bus bar 310, seek errors, replace faulty parts, perform routine checks, or disassemble a portion of the bus bar 310 to cause a voltage from the battery pack 110 to be reduced (e.g., in two or more portions of the battery pack 110).FIG. 4 illustrates an example of a battery system 300 that includes a bus bar 310 for reducing the voltage of a battery pack 110. The bus bar 310 may include a plurality (e.g., two or more) of bodies 312 that may be electrically coupled to any number of battery cells 120, such as a group of battery cells 120 in one or more battery subassemblies 115. Each body 312 may be electrically coupled to a bridge 314. Each bridge 314 may be curved downward or otherwise shaped to interact with or be coupled to a bridge connector 318, also referred to as mid-pack bus bar 318. A bridge connector 318 (e.g., the mid-pack bus bar) may electrically couple two or more bridges 314 such that the bodies 312 of the bus bar 310 are electrically coupled together. An access opening 350, which may otherwise be covered by the access cover 340, may provide a user, such as a technician or mechanic, access to a bridge connector 318, the bridges 314, and the bodies 312 of the bus bar 310.The bus bar 310 may include any one or more electrically conductive components for electrically coupling or electrically decoupling groups of battery cells 120 of a battery pack 110. The bus bar 310 may include one or more electrically conductive portions (e.g., bus bar bodies 312, bridges 314, and / or bridge connectors) for creating electrical continuity of different groups of battery cells 120 (e.g., one or more battery subassemblies 115). The bus bar 310 may include electrically conductive components (e.g., metal components) that are connected together and allow a sufficient amount of electrical conductivity to be used in high voltage and high current applications of an electric vehicle battery (e.g., about 150 to 200 kilowatts hours or about 50 to 70 amps current). The bus bar 310 may be configured, inserted, or arranged to be accessible to users (e.g., mechanic or technician) via an access opening 350. The bus bar 310 may be configured or arranged to allow a user to electrically connect or disconnect or electrically couple or decouple two or more battery cells 120, groups of battery cells 120, two or more battery subassemblies 115, groups of battery subassemblies 115, two or more battery packs 110, or groups of battery packs 110.The groups of battery cells 120 may be connected in series, in parallel, or in any combination of series and parallel configurations. A group of battery cells 120 may include any quantity or ratio of battery cells 120 of a battery pack 110. For example, a group of battery cells 120 may include one-half of all battery cells in a battery pack 110, one-third of the battery cells 120 of the battery pack, one-fourth of the battery cells, or any other ratio or fraction of the battery cells 120 in the battery pack 110, such as 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 10, 1 / 12, 1 / 16, 1 / 20, or fraction. Each of the groups of battery cells 120 may be electrically coupled to at least one of the bodies 312 of the battery pack 110.The body 312 may include any one or more electrically conductive parts or components for providing electrical continuity between the bridge 314 or bridge connector 318 and one or more battery cells 120, battery subassemblies 115, or battery packs 110. The body 312 may include a metal component (e.g., a rail or wire) that electrically couples battery cells 120, subassemblies 115, or packs 110 to a bridge connector 318. The body 312 may include a metal rail disposed between the bridge connector 318 at an end of the battery pack 110 and the battery cells 120 or subassemblies 115 inside the battery pack 110. The body 312 may be covered by an electrically insulating cover 330. The cover 330 may be a portion of the housing 344 that encloses or provides an outer surface of the battery pack 110.The bodies 312 of a bus bar 310 may be routed through the battery pack 110 to any number of groups of battery cells 120. For example, the bus bar 310 may include a first component (e.g., a first body 312) coupled to a first half of the battery pack 110 (e.g., one or more battery subassemblies 115 having a group of battery cells 120) and a second component (e.g., a second body 312) coupled to a second half of the battery pack 110. For example, the bus bar 310 may include a first body 312 coupled to a first quarter of the battery pack 110 (e.g., one or more battery subassemblies 115 having a first group of battery cells 120), a second body 312 coupled to a second quarter of the battery pack 110, a third body 312 coupled to a third quarter of the battery pack 110, and a fourth body 312 coupled to a fourth quarter of the battery pack. Each of the bodies 312 may be electrically insulated from one another (e.g., via an air gap or electrically insulating material) and may be electrically coupled to one another only via the bridge connector 318.The bridge 314 may include a component configured to connect, couple, or interface with the bridge connector 318. The bridge 314 may include an end of a body 312. The bridge 314 may be bent at an angle of 90 degrees with respect to the rest of the body 312 (e.g., a rail or rod). The bridge 314 may be curved, shaped, curved, or otherwise configured to provide a straight, lined-up, or otherwise equidistant end surface for connection to the bridge connector 318. The bridge 314 may be a portion of a body 312 or a component connected or coupled to the body 312. The bridge 314 may be shaped or configured to provide an electrical contact suitable for high current electric vehicle applications (e.g., up to 100 A current).The bridge connector 318, also referred to as mid-pack bus bar 318, may include any electrically conductive component for electrically short-circuiting or coupling two or more bodies 312 of the bus bar 310. For example, a bridge connector 318 may include a plate for connecting or coupling to a plurality of bridges 314, each of which is coupled to its own body 312 coupled to its own group of battery cells 120. The bridge connector 318 may include a flat surface plate, a curved surface plate, or any component for receiving, attaching, coupling, or otherwise connecting to one or more bridges 314 or bodies 312. The bridge connector 318 may include bolt holes to allow the bridge connector 318 to be threaded onto or attached to a bridge 314 and / or a body 312.The housing 344 may include any structure or component for enclosing, covering, or protecting any portion of the battery pack 110. The housing 344 may include panels or covers on the exterior surface of the battery pack 110, such as an end plate 342. The housing 344 may include or be connected to electrically insulating components, such as covers 330 that cover the top of the bodies 312. The end plate 342 may include a plate or plate of a material such as metal or plastic and may be used as a portion of a housing 344 on a side of a battery pack 110.An access opening 350 may include any opening through a housing 344 (e.g., an end plate 342) to provide access for servicing the bus bar 310. The access opening 350 may be covered by a removable access cover 340, which a user (e.g., technician or mechanic) may move aside or remove to gain access to a bridge connector 318 of the bus bar 310. The user may remove the bridge connector 318 to electrically decouple the bodies 312 electrically coupled to their respective groups of battery cells 120, causing the voltage output of each of the separated groups of battery cells 120 to be reduced. For example, a user may unfasten the bolts of the bridge connector 318 to decouple the bridge connector 318 from the bridge 314 of the bodies 312. This allows the user to electrically disconnect groups of battery cells 120 coupled to the bodies 312, thereby reducing the voltage and / or current of the battery pack 110. This may be useful, for example, when lower power and / or voltage output is desirable during maintenance or repair of the battery pack 110.FIG. 5 illustrates an example of a cross-sectional view of a bus bar 310 for reducing the voltage of the battery system 300. As shown in FIG. 5, the battery system 300 may include a body 312 of the bus bar 310, which may be coupled at its inner end to a battery subassembly 115 (e.g., or any other portion of a battery pack 110). The outer end of the body 312 may include a bridge 314 which may be curved, bent, shaped, or formed downward to conform to the flat surface of the bridge connector 318. Covering of the bridge connector 318 may be accomplished by an access cover 340, which may be used to cover the access opening 350 in the end plate 342. The body 312 of the bus bar 310 may be electrically coupled via fasteners (e.g., screws or brackets) to any number of battery cells 120 within one or more battery subassemblies 115 or one or more battery packs that may be electrically connected to each other and to the body 312.FIG. 6 illustrates an example of an access opening for accessing the bus bar to reduce the voltage of a battery pack 100. The access opening 350 may include an opening, a through-hole, or a passage through the end plate 342 or another portion of the housing 344 to view, access, access, and operate on the bridge connector 318 of the bus bar 310. The access opening 350 may expose screws or fasteners to the user that are used to couple the bridge 318 to the bridges 314 and / or bodies 312 of the bus bar 310.FIG. 7 illustrates an example of a plan view of the access opening and the bus bar in a battery pack. As shown in FIG. 7, the bodies 312 of the bus bar 310 may be accessible by removing the cover 330 on the top surface of the battery pack 110. Upon removal of the cover 330, the user may access screws or fasteners that couple the inner end of the body 312 to the portions of the battery pack 110 (e.g., group of battery cells 120) to which each of the bodies 312 is connected. However, access to the bridge connector 318 through the access opening 350 allows the user to decouple the bodies 312 from each other (e.g., thereby reducing battery pack voltage and battery pack current) without removing the cover 330 or removing the battery pack 110 from the EV 105. The access opening 350 may therefore allow the user to remove the bridge connector 318 and decouple portions of the battery pack 110 coupled to different bodies 312 without removing the battery pack 110 or the subassemblies 115.In some aspects, the present solution relates to a battery system 300. The battery system 300 may include a bus bar 310 for electrical coupling to a battery pack 110. The bus bar 310 may be electrically coupled between and to two groups of battery cells 120 of the battery pack 110. For example, the bus bar 310 may include a first body 312 coupled to a first group of battery cells 120 of the two groups of battery cells 120 and a second body 312 electrically coupled to a second group of battery cells 120 of the two groups of battery cells 120. The battery system 300 may include the bus bar 310 disposed at an opening of a housing 344 of the battery pack 110. The bus bar 310 may be exposed by an access cover 340. For example, an access cover 340 may occlude or cover an access opening 350 configured to allow a user (e.g., technician or mechanic) to attach a bridge connector 318 to the bodies 312 of the bus bar 310, thereby electrically coupling the bodies 312 and their respective groups of battery cells 120. Similarly, the access opening 350 may allow a user (e.g., a technician or mechanic) to remove a bridge connector 318 from the bodies 312 of the bus bar 310, thereby electrically decoupling the bodies 312 and their respective groups of battery cells 120.The battery system 300 may include the bus bar 310, which includes one or more bodies 312. Each of the bodies 312 may be electrically coupled to one or more bridges 314. A bridge 314 may include an electrically conductive (e.g., metallic) component. The bridge 314 may be shaped, formed, or configured to provide a tight physical and electrical connection to the bridge connector 318 and / or the body 312. The bridge 314 may be an integral component or part (e.g., an end) of the body 312. The bridge 314 may be curved relative to the body 312. For example, bridge 314 may be bent 90 degrees with respect to the body (e.g., form a right angle with body 312). The bridge 314 may be disposed within the housing 344 and may be exposed (e.g., for inspection, debugging, fixation, or alignment) by removing the access cover 340.The battery system 300 may include the bus bar 310, which includes a body 312 and a bridge 314. For example, a bus bar 310 may include one or more bodies 312. Each of the bodies 312 may be electrically insulated from other bodies 312 of the bus bar 310, except via the bridge 318. The bridge connector 318 may electrically couple the bodies 312 of the bus bar 310 to a single electrically conductive component. A cover 330 may include an electrically insulating material and may be disposed over one or more bodies 312. The cover 330 may cover a portion of the body 312 or an entire body 312.The battery system 300 may include the bus bar 310, which may be coupled to the battery pack 110 at a midpoint between the two groups of battery cells 120. For example, the bus bar 310 may be disposed on or near a surface (e.g., top or bottom surface) of the battery pack 110. The bus bar 310 may include a first body 312 electrically coupled to a half of the battery cells 120 (e.g., a left side of the battery pack 110 with one or more battery subassemblies 115 filled with battery cells 120). The bus bar 310 may include a second body 312 electrically coupled to a second half of the battery cells 120 (e.g., a right side of the battery pack 110 with one or more battery subassemblies 115 filled with battery cells 120). The bus bar 310 may thereby allow the battery cells 120 of both halves of the battery pack 110 to be connected together (e.g., in series to provide a maximum voltage) via a bridge connector 318. Once a bridge connector 318 is removed, the two halves of the battery pack 110 may provide one half of their maximum voltage output when connected via the bridge connector 318.The battery system 300 may include a first body 312 of the bus bar 310 electrically coupled to a first group of the two groups of battery cells 120 and a second body 312 of the bus bar 312 electrically coupled to a second group of the two groups of battery cells 120. The first group of battery cells 120 may include a half of the battery cells 120 of the battery pack 110 (e.g., when the bus bar 310 includes two bodies 312), a third of the battery cells 120 of the battery pack 110 (e.g., when the bus bar 310 includes three bodies 312), a quarter of the battery cells 120 (e.g., when the bus bar 310 includes four bodies 312), and so forth. The remaining bodies 312, such as the second body 312, may be connected to the second group of battery cells 120. For example, a third body 312 may be connected to a third group of the battery cells 120. For example, a fourth body 312 may be connected to a fourth group of the battery cells 120.The battery system 300 may include the bus bar 310 disposed on an end plate 342 of the housing 344. The housing 310 may be disposed proximate an end plate 342 of the housing 344. For example, the bridge connector 318 may be disposed adjacent to or within the end plate 342. For example, the bridge connector 318 of the bus bar 310 may be disposed, located, formed, or placed within the access opening 350 that lies within the end plate 342. The bridge connector 318 of the bus bar 310 and the bus bar 310 may pass adjacent, adjacent, adjacent, or otherwise against the plate 342 or any surface of the housing 344 (e.g., top or surface of the housing 344, bottom or surface of the housing 344, one of the side surfaces of the housing 344, front or back of the housing 344).The battery system 300 may include a bridge connector 318 that electrically couples a first body 312 of the bus bar 310 to the second body 312 of the bus bar 310. The bridge connector 318 may be removable on an end plate of the housing 344 via an access opening 350 of the access cover 340. Removing the bridge connector 318 may cause a first group of the two groups of battery cells 120 to be electrically decoupled from a second group of the two groups of battery cells 120. For example, if the bus bar 312 includes more than two bodies 312, each of the groups of battery cells 120 coupled to each of the bodies 312 may be electrically decoupled by removing the bridge connector 318, and electrically coupled by placing, installing to, or connecting the bridge connector 318 to the bodies 312 (e.g., or the bridges 314).The battery system 300 may include a bridge connector 318 that electrically couples a first bridge 314 of a first body 312 of the bus bar 310 coupled to a first group of the two groups of the battery cells 120 to a second bridge 314 of a second body 312 of the bus bar 310 coupled to a second group of the two groups of the battery cells 312. The bridge connector 318 may be configured to electrically decouple a first group of the two groups of the battery cells 120 from a second group of the two groups of the battery cells 120 by removing the bridge connector 318 from a bridge 314 of a body 312 of the bus bar 310.The battery system 300 may include a second bus bar 310 to electrically couple the battery pack 110 to a second battery pack 110. The battery system 300 may include a second bridge connector 318 that electrically couples a first bridge 314 of a first body 312 of the second bus bar 310 coupled to the battery pack 110 to a second bridge 314 of a second body 312 of the second bus bar 310 coupled to the second battery pack 110. For example, the bridge connector 318 may electrically couple any number of bodies 312 coupled to their respective groups of battery cells 120 via their respective bridge 314. The battery system 300 may include a second bridge connector 318 configured to electrically decouple the battery pack 110 from the second battery pack 110 by removing the second bridge connector 318 from a bridge 314 of a body 312 of the second bus bar 310 via an access opening 350.In some aspects, the present disclosure relates to a battery system 300 of an electric vehicle 105. The battery system 300 may include a bus bar 310 for electrically coupling to a battery pack 110 between two groups of battery cells of the battery pack 110. The bus bar 310 may be disposed at an opening of a housing 344 of the battery pack 110. The bus bar 310 may be exposed by an access cover 340. The battery system may include a bridge connector 318 to electrically couple a first body 312 of the bus bar 310 to the second body 312 of the bus bar 310. The bridge connector 318 may be removable via the access cover 340 on an end plate of the housing 344 to cause a first group of the two groups of battery cells 120 electrically coupled to the first body to be electrically decoupled from a second group of the two groups of battery cells 120 electrically coupled to the second body.FIG. 8 shows a method 800 for providing a bus bar of a battery pack for accessing to electrically decouple at least a portion of a battery pack via the bus bar. The method 800 may also be directed to reducing the voltage of a battery pack using a bus bar of the battery pack or electrically decoupling at least a portion of a battery pack. The method 800 may be implemented, for example, using components or features of the battery system 300 discussed in FIGS. 3-7. At OPERATION 805, the method may include electrically coupling a bus bar. At OPERATION 810, the method may include disposing the bus bar at an opening. At OPERATION 815, the method may include exposing the bus bar for access by an access cover.At OPERATION 805, the method may include electrically coupling a bus bar. The method may include electrically coupling a bus bar to two groups of battery cells of a battery pack. For example, the bus bar may be formed to include a body of the bus bar and a bridge of the bus bar. The bridge of the bus bar may be formed, shaped, or configured to be bent relative to the body of the bus bar. The bridge and the body may be located within the housing of the battery pack. The bridge and body may be configured to comprise electrically conductive material (e.g., metal) and may include a single structure or component or multiple structures or components. The bridge may be formed, configured, or shaped to form a physical and electrical contact with the bridge connector.The method may include providing a first body of the bus bar electrically coupled to a first group of the two groups of battery cells. The first body may include an electrically conductive rod, wire, or rail, as well as one or more components that may be in electrical continuity with a group of battery cells. The group of battery cells may include the battery cells of one or more battery subassemblies. The group of battery cells may include the battery cells within a single battery subassembly. The group of battery cells may include, for example, one half of the battery cells of the battery pack, one third of the battery cells of the battery pack, one quarter of the battery cells of the battery pack, or any other portion of the battery cells, such as 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9, 1 / 10, 1 / 16, or less than 1 / 16 of the battery cells. Each of the groups of battery cells may be coupled to its own body of the bus bar.The method may include providing a second body of the bus bar electrically coupled to a second group of the two groups of battery cells. The second body of the bus bar may be electrically insulated from the first body of the bus bar except for electrical contact via the bridge connector. The second body of the bus bar may be spaced apart from the first body of the bus bar. For example, in configurations in which more than two bodies are included, all bodies of the bus bar may be spaced apart from one another. The second body of the bus bar may be electrically coupled to the second group of battery cells, which may include any amount or fraction of battery cells of the battery pack, such as a half, a third, a quarter, 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9, 1 / 10, 1 / 16, or less than 1 / 16 of the battery cells.The method may include providing a first body of the bus bar with a first bridge exposed for access via the access cover. The method may include providing a second body of the bus bar with a second bridge exposed for access via the access cover. A bridge connector of the bus bar may electrically couple the first body to the second body via the first bridge. Coupling the first body and the second body via the bridge connector may cause a first group of the two groups of battery cells to be electrically coupled to the first body to be electrically coupled to a second group of the two groups of battery cells electrically coupled to the second body. The bridge connector may be removable via the access cover on an end plate of the housing. The bridge connector may be removable by removing fasteners or screws that couple the bridge connector to the bridges or bodies of the bus bar.At OPERATION 810, the method may include disposing the bus bar at an opening. The method may include disposing the bus bar at an opening of a housing of the battery pack. The bus bar may be disposed at an opening in an end plate, a front plate, a side plate, an upper plate, or a lower plate or surface of the housing. The busbar can be arranged to be accessible to a user (e.g. a mechanic or a technician) via the opening of its end (e.g. connecting side of the busbar to the bridge). The method may include providing the bus bar with a body electrically coupled to a bridge. For example, the bridge and the bus bar may be integrated or formed in a single structure or component, or may include multiple structures electrically coupled together.The method may include providing a cover arranged to cover a portion of the body. The cover may be formed using an electrically insulating material such as plastic. The cover may be removable to provide access to the portion of the body of the bus bar. The cover may be integrated with or coupled to the housing or a plate of the battery pack (e.g., end plate or top plate). The method may include electrically coupling the bus bar to the battery pack at a midpoint between the two groups of battery cells. For example, the bus bar may be disposed in the central portion of the battery pack such that a first body of the bus bar on the left side of the battery pack may be coupled to the battery cells on the left side of the battery pack and the second body of the bus bar on the right side of the battery pack may be coupled to the battery cells on the right side of the battery pack. The method may include disposing the bus bar for access via an access opening of the access cover to an end plate of the housing.At OPERATION 815, the method may include exposing the bus bar for access by or via an access cover. The method may include exposing the bus bar for access by an access cover via the opening. For example, the bus bar may be exposed for access by a user (e.g., a technician or mechanic) via the opening from which the cover may be removed. The method may include exposing the bridge of the bus bar by removing the access cover. For example, the cover may be removed to expose the bridge side of the bodies of the bus bar. An access cover may cover the access opening and may be movable, slidable, or removable from the access opening to expose the bridge connector at an end of the bus bar.The method may include providing a bridge connector that electrically couples a first bridge of a first body of the bus bar coupled to a first group of the two groups of the battery cells to a second bridge of a second body of the bus bar coupled to a second group of the two groups of the battery cells. For example, the bridge connector may be provided or exposed for access by a user via the access opening to allow the user to electrically decouple the bodies of the bus bar from each other by removing the bridge connector. The bridge connector may be configured to electrically decouple the first group of the two groups of battery cells from the second group of the two groups of battery cells by removing the bridge connector via an access opening of the access cover.The method may include electrically coupling, by a second bus bar, the battery pack to a second battery pack. For example, the second bus bar may be provided to couple one battery pack having a plurality of battery subassemblies and / or battery cells to another battery pack having a plurality of battery subassemblies and / or battery cells. The second bus bar may include the same or similar structural and functional features as the bus bar. The second bus bar may include a second bridge connector that electrically couples a first bridge of a first body of the second bus bar coupled to the battery pack to a second bridge of a second body of the second bus bar coupled to the second battery pack. The second bridge connector may be configured to electrically decouple the battery pack from the second battery pack by removing the second bridge connector from a bridge of a body of the second bus bar.The systems described above may provide multiple ones of any or each of these components, and these components may be provided on either a stand-alone system or on multiple instantiations in a distributed system.Examples and non-limiting module implementing elements include sensors that provide a value determined herein, sensors that provide a value that is a precursor of a value determined herein, data connections or network hardware including communication chips, crystal, communication connections, cable, twisted pair cable, coaxial cable, shielded cable, transmitter, receiver or transmitter-receiver, logic circuits, hardwired logic circuits, reconfigurable logic circuits in a particular non-volatile state configured according to the module specification, an actuator including at least one electrical, hydraulic or pneumatic actuator, a solenoid, an operational amplifier, analog control elements (springs, filters, integrators, adders, dividers, gain elements), or digital control elements.Although the operations are depicted in the drawings in a particular order, it is not necessary for these operations to be performed in the order shown, and not all illustrated operations need to be performed. The actions described herein may be performed in a different order.Having now described some illustrative implementations, it will be apparent that the foregoing is illustrative and not restrictive, as it has been presented by way of example. Although many of the examples presented herein include specific combinations of methods or system elements, these acts and elements may be combined in other ways to achieve the same goals. Acts, elements, and features discussed in connection with an implementation are not intended to be excluded from a similar role in other implementations or implementations.The terminology used herein is for the purpose of description and should not be considered as limiting. The use of "including", "comprising", "including", "containing", "including", "characterized by", "characterized in that", and variations thereof herein is intended to include the items listed below, their equivalents and additional items, as well as alternative implementations consisting solely of the items listed below. In one implementation, the systems and methods described herein consist of any combination of more than one or all of the described elements, acts, or components.Any reference to implementations or elements or acts of the systems and methods referred to herein in the singular may also include implementations including a plurality of these elements, and any reference to an implementation or element or act herein in the plural may also include implementations including only a single element. References in the singular or plural are not intended to limit the presently disclosed systems or methods, their components, acts, or elements to single or multiple configurations. References to an action or element being based on information, action, or element may include implementations where the action or element is based at least in part on information, action, or element.Each implementation disclosed herein may be combined with any other implementation or embodiment, and references to "one implementation", "some implementations", "one implementation", or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the implementation may be included in at least one implementation or embodiment. The terms used herein do not necessarily all refer to the same implementation. Each implementation may be combined with any other implementation, including or excluding, in any manner consistent with the aspects and implementations disclosed herein.References to "or" may be understood to be inclusive, such that any term described with "or" may refer to a single, more than one, or all of the described terms. References to at least one term from a conjunctival list of terms may be construed as an inclusive OR to refer to a single, more than one, or all of the terms described. For example, a reference to "at least one" of "A" and "B" may include both only "A", only "B", and both "A" and "B". Such references used in connection with "comprising" or other open terminology may include other items.Where technical features in the drawings, the detailed description, or a claim are followed by reference numerals, the reference numerals have been included to enhance the intelligibility of the drawings, the detailed description, and the claims. Therefore, neither the reference numerals nor their lack have a limiting effect on the scope of the individual claim elements.Modifications to the described elements and acts, such as variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, arrangements for mounting, use of materials, colors, orientations, may occur without materially compromising the teachings and advantages of the subject matter disclosed herein. For example, elements shown as integral may be comprised of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the type or number of individual elements or positions may be varied or varied. Other substitutions, modifications, changes, and omissions may also be made in the design, operating state, and arrangement of the disclosed elements and operations without departing from the scope of the present disclosure.For example, descriptions of positive and negative electrical properties may be reversed. For example, the positive or negative polarity of the battery cells 120, battery subassemblies 115, or battery pack 110 may be reversed. Elements described as negative elements may instead be configured as positive elements, and elements described as positive elements may instead be configured as negative elements. For example, elements described as having a first polarity may instead have a second polarity, and elements described as having a second polarity may instead have a first polarity. Other relative parallel, perpendicular, vertical, or other positioning or orientation descriptions include variations within + / -10% or + / -10 degrees of pure vertical, parallel, or perpendicular positioning. References to "about," "substantially," or other terms include + / -10% variations from the stated measurement, unit, or range, unless expressly stated otherwise. Coupled elements may be electrically, mechanically, or physically coupled together, directly, or with intervening elements. The scope of the systems and methods described herein will therefore be apparent from the appended claims rather than from the foregoing description, and changes which come within the meaning and range of equivalence of the claims are intended to be embraced therein.
Claims
A system comprising: a bus bar for electrically coupling to a battery pack between two groups of battery cells of the battery pack, the bus bar disposed at an opening of a housing of the battery pack, the bus bar to be exposed by an access cover.The system of claim 1, wherein the system comprises the bus bar comprising a body and a bridge, the bridge being bent relative to the body, the bridge to be within the housing, and to be exposed by removing the access cover.The system of claim 1, wherein the system comprises the bus bar including a body and a bridge, a cover disposed to cover a portion of the body.The system of claim 1, wherein the system comprises the bus bar for coupling to the battery pack at a mid-location between the two groups of battery cells.The system of claim 1, wherein the system comprises a first body of the bus bar electrically coupled to a first group of the two groups of battery cells and a second body of the bus bar electrically coupled to a second group of the two groups of battery cells.The system of claim 1, wherein the system comprises the bus bar for placement on an end plate of the housing.The system of claim 1, wherein the system comprises a bridge connector that electrically couples a first body of the bus bar to the second body of the bus bar, wherein the bridge connector is removable via an access opening of the access cover on an end plate of the housing to electrically decouple a first group of the two groups of battery cells from a second group of the two groups of battery cells.The system of claim 1, wherein the system comprises a bridge connector that electrically couples a first bridge of a first body of the bus bar coupled to a first group of the two groups of the battery cells to a second bridge of a second body of the bus bar coupled to a second group of the two groups of the battery cells.The system of claim 1, wherein the system comprises a bridge connector configured to electrically decouple a first group of the two groups of the battery cells from a second group of the two groups of the battery cells by removing the bridge connector from a bridge of a body of the bus bar.The system of claim 1, wherein the system comprises a second bus bar to electrically couple the battery pack to a second battery pack.The system of claim 10, wherein the system comprises a second bridge connector that electrically couples a first bridge of a first body of the second bus bar coupled to the battery pack to a second bridge of a second body of the second bus bar coupled to the second battery pack.The system of claim 10, wherein the system comprises a second bridge connector configured to electrically decouple the battery pack from the second battery pack by removing the second bridge connector from a bridge of a body of the second bus bar via an access opening.A method of electrically decoupling at least a portion of a battery pack, comprising: electrically coupling a bus bar to two groups of battery cells of a battery pack; disposing the bus bar at an opening of a housing of the battery pack; and exposing the bus bar for access through an access cover via the opening.The method of claim 13, comprising: forming the bus bar to include a body of the bus bar and a bridge of the bus bar bent relative to the body, the bridge to be within the housing; and exposing the bridge of the bus bar by removing the access cover.The method of claim 13, comprising: providing the bus bar with a body electrically coupled to a bridge; providing a cover disposed to cover a portion of the body; and electrically coupling the bus bar to the battery pack at a midpoint between the two groups of battery cells.The method of claim 13, comprising: providing a first body of the bus bar electrically coupled to a first group of the two groups of battery cells; providing a second body of the bus bar electrically coupled to a second group of the two groups of battery cells; and disposing the bus bar for access via an access opening of the access cover on an end plate of the housing.The method of claim 13, comprising: providing a first body of the bus bar with a first bridge exposed for access via the access cover; providing a second body of the bus bar with a second bridge exposed for access via the access cover; electrically coupling the first body via the first bridge to the second body via the second bridge via a bridge connector to cause a first group of the two groups of battery cells electrically coupled to the first body to be electrically coupled to a second group of the two groups of battery cells electrically coupled to the second body, wherein the bridge connector is removable via the access cover at an end plate of the housing.The method of claim 13, comprising: providing a bridge connector that electrically couples a first bridge of a first body of the bus bar coupled to a first group of the two groups of battery cells to a second bridge of a second body of the bus bar coupled to a second group of the two groups of battery cells, wherein the bridge connector is configured to electrically decouple the first group of the two groups of battery cells from the second group of the two groups of battery cells by removing the bridge connector via an access opening of the access cover.The method of claim 13, comprising: electrically coupling, by a second bus bar, the battery pack to a second battery pack; electrically coupling a first bridge of a first body of the second bus bar coupled to the battery pack to a second bridge of a second body of the second bus bar coupled to the second battery pack by a second bridge connector, the second bridge connector configured to electrically decouple the battery pack from the second battery pack by removing the second bridge connector from a bridge of a body of the second bus bar.A battery system of an electric vehicle, the battery system comprising: a bus bar for electrically coupling to a battery pack between two groups of battery cells of the battery pack, the bus bar disposed at an opening of a housing of the battery pack, the bus bar to be exposed by an access cover; and a bridge connector for electrically coupling a first body of the bus bar to the second body of the bus bar, the bridge connector being removable via the access cover on an end plate of the housing to electrically decouple a first group of the two groups of battery cells electrically coupled to the first body from a second group of the two groups of battery cells electrically coupled to the second body.