A published patent application lags its filing by roughly 18 months, so the batch GM Global Technology Operations LLC had published the week of April 30, 2026 is a record of where the automaker was committing battery R&D in late 2024. Across about twenty published applications that week, much of the vehicle-tech volume is in driver assistance, steer-by-wire, and keyless-entry ranging — but a distinct battery cluster runs through the set, and it points consistently inward, at the pack: how to cool it, how to safely vent it, how to warm it in the cold, and how to catch a failing cell before it propagates.

The thermal-propagation work is the anchor. US20260121162A1 describes a prismatic battery assembly with an air-flow inlet and outlet and an internal air-flow channel connected to a vent channel, with an air-flow source that directs flow to draw heated vent gases out of the assembly.

The air flow draws heated vent gasses away from the prismatic battery assembly.— Battery enclosure with air flow channel for cooling during thermal propagation, US20260121162A1

That framing — actively moving hot vent gas out of the enclosure during propagation — sits alongside US20260121152A1, which claims a steel prismatic battery can with a thermally conductive junction between the electrode assembly and the can bottom, fixed to the inside surface so it conducts heat while electrically isolating the electrode edges. The repeated appearance of prismatic-format hardware is itself a signal: these filings point to design work on prismatic cells specifically, a format choice with implications for how a pack is cooled and contained.

Cold starts, soft-shorts, and the power path

A second thread addresses temperature at the other extreme. US20260121150A1 describes a multi-branch coolant system for enhancing cold-start discharge power: when the rechargeable energy-storage system is at or below a set temperature, a controller heats the coolant and shuts off flow to non-selected modules so that selected modules are warmed first. Pairing active venting for hot events with selective heating for cold ones indicates R&D aimed at the full temperature envelope a vehicle pack faces, not a single failure mode.

Diagnostics form a third thread. US20260118437A1 covers a system for detecting a soft-short in a battery by measuring impedance at multiple frequency points using electrochemical impedance spectroscopy, counting how often a calculated error exceeds a threshold, and flagging the cell when the count crosses a limit. A soft internal short is an early indicator of the kind of defect that can lead to a thermal event, so a method to detect one connects directly to the venting-and-cooling work above.

The cluster also reaches the power electronics that move energy through the pack. US20260122864A1 describes a power-inverter module in a molded composite housing with a coolant block in direct thermal engagement with the semiconductor switches, and US20260122760A1 covers a liquid-cooled PCB holder affixed to a motor rotor shaft for inductive power transfer and inverter electronics. The CPC tags across the battery applications concentrate in H01M 10/613, 10/625, and 10/635 (thermal management of cells) plus H01M 10/647 and 10/6564 (cooling structures) — consistent with a portfolio thread centered on keeping the pack within temperature, rather than on cell chemistry.

None of these filings is a product, and a published application is not a commitment to build. What the week shows is direction: in the late-2024 applications now surfacing, GM was concentrating battery R&D on the thermal and diagnostic side of its own packs — drawing vent gas out of prismatic cells, conducting heat through a steel can, warming modules selectively for cold starts, and detecting soft-shorts by impedance. Those are the threads the records point to, attached to the specific application numbers above.