EV Battery Pack Design for Safety and Performance

Securing electronics modules within a traction battery pack assembly by suspending them from the enclosure cover. The battery pack has an enclosure with a removable cover. An electronics support plate is secured to the cover using brackets and fasteners. The electronics modules are mounted on the support plate. This allows the modules to be easily accessed and serviced by removing the cover, without having to disconnect wiring harnesses and other connections.

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Monitoring swelling of battery containers without internal sensors by attaching an external strain gauge to a tightening strap around the battery. The strap has a tightening mechanism to pull it taut against the battery container when swelling occurs. The strain gauge stretches with the container expansion and is connected to an electronics package that reads the gauge and transmits the strain data to a battery management system.

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Solid electrolyte for lithium batteries that can inhibit cracking and delamination in the electrode layers, reducing battery resistance. The solid electrolyte has a specific breaking energy of over 21.4 J/cm³ when compressed into a pellet. This high energy absorbing property prevents cracking and peeling of the electrode layers during charge/discharge cycling.

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Battery box design for electric vehicles that improves thermal management and reduces temperature differences between battery cells. The battery box has side plates and a bottom plate with internal partitions to form multiple flow channels. The cooling liquid flows through the channels all in the same direction, which provides uniform cooling to the cells in a perpendicular direction compared to the traditional U-shaped flow path. This improves heat exchange uniformity and reduces cell temperature variations.

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Apparatus and method for manufacturing lead tabs for secondary batteries that improves adhesion with the battery sealant and prevents corrosion. The method involves defining processing patterns on the upper and lower surfaces of the lead tab using laser marking. This is done after cutting the lead tabs to size rather than on the long unwound sheet to maintain precise pattern spacing. The lead tabs are then coated with PVA adhesive, cured with UV light, and dried with hot air. This provides a stable adhesive layer between the lead tab and battery sealant without corrosion. The lead tabs are also stabilized by heating to form an oxidation film before cooling.

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Battery cell design to improve safety and reliability. The battery cell has a housing with an inner cavity, an electrode assembly, terminals, and a pressure relief component on the housing wall. The relief component has a weakened section that opens at a specific pressure inside the cell. This prevents explosions by controlled venting at safe pressures. The weakened section thickness is within a range to balance opening reliability during thermal runaway vs strength under normal conditions.

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A separator for lithium-ion batteries with improved cycle life and swelling resistance. The separator has a coating on one side that has a thinner central region surrounded by a thicker edge region. This configuration allows the separator to accommodate battery swelling better during charging/discharging cycles compared to a uniform coating thickness. The thinner central region reduces swelling force on the electrolyte, improving solution retention, and the thicker edge region provides mechanical support.

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Battery cell design to mitigate high temperature failure by self-discharging when cell temperatures reach levels indicative of failure. The cells have thermal fuses between the electrodes and current collectors that melt at elevated temperatures. This creates a conductive path between oppositely polar electrodes to discharge the cell when it overheats, preventing internal damage from spreading and potentially isolating thermal runaway.

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A selectable shim system for applying compression to battery cell stacks in a traction battery pack. The shims are inserted between the cell stacks and the pack enclosure walls to provide a desired preload on the cells. By measuring the cell stack and enclosure dimensions, appropriate shims can be selected.

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A battery module system for electric vehicles that provides improved structural rigidity to the vehicle frame while housing the batteries. The system uses a container mounted to the vehicle frame rails to enclose the battery assemblies. This container with higher walls acts as a structural member in the vehicle frame, adding torsional rigidity.

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Traction battery pack for electric vehicles that securely attaches the pack cover to internal components to prevent detachment during vehicle operation. The attachment mechanisms connect the cover directly to separators within the battery pack instead of just the outer housing. This maintains cover retention at interior regions of the battery pack, keeps the cover spaced apart from the cells, and creates a desired amount of pack-level stiffness for load distribution. The attachments can be clips, adhesives, magnets, fasteners, ball-and-socket joints, etc.

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Optimizing the design of battery packs for electric vehicles that house cell stacks within irregularly shaped enclosures, to enable easier insertion of compressed cells into this opening and compression of cells between the irregular surfaces. It involves a block insert that interfaces between the irregular enclosure and cell stack. This insert allows compressing the cells to fit through the opening by providing a flat interface, while transferring compression loads from the enclosure walls to the cells through a curved interface.

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Lithium-ion battery electrodes with a unique non-uniform porous structure that enhances performance compared to conventional electrodes. The positive electrode is made by setting the porosity of the surface layer higher with larger active material particles compared to the inner layer. This non-uniform structure improves battery rate performance and capacity retention by reducing resistance and impedance.

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A battery module with reduced weight containing battery cells, a frame, a busbar frame, and an end plate that covers the busbar frame. The end plate consists of an insulating portion in contact with the busbar frame and a reinforcing portion inserted into the insulating portion. This maintains weldability and rigidity while reducing weight. The battery module is used in battery packs like those for electric vehicles.

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Method of assembling a traction battery pack by engaging an enclosure structure with manufacturing equipment, changing the size of the cell-receiving opening using the manufacturing equipment, inserting at least one cell stack into the opening, and disengaging the manufacturing equipment. The enclosure structure then compresses the cell stack. The opening is changed to allow insertion of the cell stack perpendicular to its axis.

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Method to compress and hold battery cells in a traction battery pack for vehicles. A compressing wall is moved against the cells to apply a compressive force between the wall and the enclosure structure. The wall is then secured to hold the cells in position. This compresses the cells to reduce movement. The compressing wall is positioned within the pack after the cells are loaded.

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Degassing unit for a housing, like a battery, with a base that attaches to the housing and a membrane covering an opening in the base. The membrane has weakened areas that reduce the pressure needed to burst and open the opening. The weakening can be done through localized treatments like laser melting or mechanical scoring. This allows the membrane to have lower bursting pressures than an untreated membrane.

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Assembly method for traction battery packs for electric vehicles. The process involves compressing multiple battery cell stacks using fixtures, then inserting the compressed stacks into an enclosure structure. After insertion, the enclosure compresses the stacks further. This staged compression allows high density packing of the battery cells without damaging them.

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A technique for assembling battery packs that simplifies the process and reduces the risk of damage to components, particularly prismatic cell stacks, during insertion into an enclosure. The technique involves holding the cell stack with a compression machine that engages load plates on either end. The compressed stack is aligned with the enclosure opening and inserted. The compression machine is then disengaged. The compression method prevents stack expansion and distortion when inserting into the enclosure.

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Standoff assembly to separate enclosure cover and battery cells in battery packs for electric vehicles. The standoff assembly maintains a gap between the enclosure cover and battery cell components. It could be positioned between the cover and the cell stack or between the cover and the battery system. The standoffs prevent contact between the battery cells and enclosure and maintain a space for compression of the cells. It allows compressing the cell stack within the pack while avoiding pressure on the cover that could damage the cells.

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