Tesla's energy business sells two batteries that look like completely different products because they are aimed at completely different jobs. One sits on a garage wall; the other is the size of a shipping container and shows up by the dozen at a substation. Tesla's Form 10-K for fiscal 2021 describes both, and the contrast is a clean way to understand energy storage in general.
The filing groups them together: Powerwall and Megapack are described as Tesla's lithium-ion battery energy storage products. The shared idea is simple — store electricity when it is plentiful or cheap, release it when it is scarce or expensive. What changes from one product to the other is scale and customer.
Powerwall is the home product. Per the filing it is designed for residential use — the everyday jobs are backing up a house when the grid goes down and storing power from rooftop solar so a household can use its own sunshine after dark. Its value to a homeowner is resilience and self-consumption: keeping the lights on, and using more of the solar you already paid for instead of exporting it cheaply.
Megapack is the grid product. It is a utility-scale system, assembled in the factory as a large pre-integrated unit so that a developer can deploy many of them quickly to build a big storage installation. The job here is grid-scale: storing energy across a whole power system, smoothing the mismatch between when renewable generation is available and when demand peaks, and providing services that help keep the grid stable. One Megapack is meaningless; a field of them is a power plant that runs on stored electricity.
The reason to keep the two straight is that 'Tesla battery deployments' can mean either, and they imply different things about the business. Powerwall volume is a consumer-and-installer story tied to rooftop solar. Megapack volume is a story about utilities and large developers buying grid storage — a market that is growing as more wind and solar come online and need something to firm them up. The filing reports the energy segment as a whole, but understanding the segment means knowing these are two distinct demand engines.
For the real product definitions and how Tesla itself frames them, the annual report is the source rather than a configurator page. You can pull the filing — indexed through tools like EdgarBeast — and read the storage-products description directly.