MG’s Semi‑Solid‑State Battery: A Different Kind of EV Power
When MG Motor launched the MG4 with a semi solid state battery in China, it claimed the world’s first mass‑produced electric vehicle using this chemistry—and plans to bring it to Europe by the end of 2026. Unlike today’s typical lithium‑ion packs, which rely on liquid electrolytes, MG’s electric vehicle battery uses a mix of solid and liquid, sometimes gel‑like, materials. This semi‑solid approach promises higher energy density, faster charging, better cold‑weather performance, and improved safety thanks to reduced risk of leakage and thermal runaway. In China, the MG4 delivers an estimated 330 miles of range and has been positioned as a benchmark‑setting EV platform. MG expects to roll this high‑tech pack into other models, signalling that semi‑solid‑state designs are moving out of the lab and into real cars. That shift matters not only for driving range, but for what happens to these batteries after their first life on the road.
From Model 3 to Home Battery: Inside a 79 kWh Tesla Solar System
In Germany, a Tesla owner has demonstrated how a used EV pack can anchor a powerful EV home energy storage setup. A retired Tesla Model 3 battery was repurposed into a 79 kWh home system, charged by 11 kW of rooftop solar. The result is a battery bank capable of running a typical household for roughly three to five days, depending on consumption. Compared to a Tesla Powerwall 3 at about 13.5 kWh, this DIY Tesla battery solar system offers nearly six times the storage capacity. Because stationary systems are not constrained by weight or space, a pack that feels “degraded” in a car can still deliver strong value in a fixed installation. This project is an early, real‑world example of how second life EV batteries can extend their usefulness, support solar self‑consumption, and boost energy independence long after their prime driving years.
Why Semi‑Solid‑State Packs Are Built for a Strong Second Life
Semi solid state battery designs like MG’s could be ideal candidates for second life EV batteries once their automotive performance fades. EV packs are typically considered for replacement when range loss becomes noticeable, even though they may retain most of their original capacity. In a car, every kilometre of range and kilogram of weight matters; in a stationary system, the priorities shift to safety, cycle life, and predictable performance. Semi‑solid‑state chemistries, with improved thermal stability and potentially longer lifespans, line up well with those needs. If automakers scale mass production of such batteries, tomorrow’s retired MG electric vehicle battery or similar packs could become the core of home or community storage systems. That would turn each EV into a future energy asset, designed from day one not only to power mobility but also to support homes, businesses, and local grids in a second, stationary life.
Cutting Costs and Carbon: The Promise and Pitfalls of Second‑Life Storage
As more first‑generation EVs age, second life EV batteries offer a way to lower costs and reduce waste in home energy storage. Repurposed packs delay recycling, squeezing extra years of service out of mined materials and factory‑built hardware. Projects like the German Tesla system show how large‑capacity second‑life storage could undercut the cost per kWh of new products, making solar‑plus‑storage more attractive. They can also strengthen resilience in areas with grid instability or high tariffs, letting households store cheap or solar power and ride through outages. Yet there are hurdles: safety standards for refurbished packs, clear warranties, and liability if a used battery fails. Key questions remain over who owns the pack at end‑of‑life—the car maker, the finance company, or the driver—and whether DIY conversions can ever be mainstream. Most analysts expect professional, manufacturer‑backed refurbishment and integration programs to dominate over hobbyist builds.
Why This Matters for Malaysia’s Solar Future
For Malaysia and the wider region, the convergence of semi‑solid‑state innovation and second‑life storage could be pivotal. Interest in rooftop solar is rising as households look to hedge against future TNB tariff increases and improve energy independence. Today, high upfront costs for batteries still limit widespread EV home energy storage adoption. Over the coming years, however, growing EV uptake will create a pipeline of used packs—especially as models with more durable chemistries, such as semi‑solid‑state designs, enter the fleet. Properly regulated, those retired batteries could be aggregated into affordable home systems or neighbourhood‑scale storage, capturing daytime solar and supplying evening demand. Policymakers will need to set clear rules on repurposing, safety certification, and data access so installers can integrate second‑life batteries confidently. If done well, Malaysia could transform yesterday’s EV batteries into tomorrow’s silent, solar‑charged backup for homes and small businesses.