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> cheap as dirt There are lots of things left to make grid battery storage cheap. As well as the cells needing to be engineered to be cheaper, there are lots

> cheap as dirt There are lots of things left to make grid battery storage cheap. As well as the cells needing to be engineered to be cheaper, there are lots of changes to the battery packs that can be made, together with changes to inverters. For batteries, I'd like to see research into less consistent manufacturing and higher failure rates. Current packs the entire pack is unusable if just one cell fails in a way that leads to lots of heat production. If pack balancing circuits had the ability to take a cell or a parallel group of cells 'out of circuit' while still using the rest of the pack, then battery lifespans could be dramatically increased and it would be possible to manufacture cells far cheaper. For inverters, we should go for a direct-to-10kV inverter process. No transformers. At 10kV, currents are far lower and therefore wires can be far thinner (and cheaper). Consider making batteries ~15kV too - that reduces by ~30% the amount of expensive silicon needed, together with big reductions in copper costs, at the expense of extra design effort for much higher voltage batteries. At these higher voltages, you'd either use oil cooling, or you'd have ~10 separate coolant loops, one at each ~1500 volts of potential.

garbageman 3y ago
While it would be neat to build batteries that handle manufacturing defects akin to a CPU with 4 cores but 3 useable, I suspect the additional complexity, wiring, and circuitry is limiting. Batteries today are almost (or actually?) a commodity. Detecting and simply replacing the entire battery is probably cheaper and easier at grid scale.
- londons_explore 3y ago
  The wiring and complexity isn't very much - you simply need a contactor that can 'short' the offending set of cells. It only needs to close once, so can simply be made from a spring and meltable material. And you need ~100 of these per 400 volt battery. Beyond that, all the complexity is in software. Software needs to monitor cell voltages and currents to detect a self-heating cell. Software then needs to stop balancing that cell up (ie. let it discharge). At the moment the cell voltage hits zero, software needs to close the 'short' across the cell, permanently taking it out of the circuit. This design might occasionally prevent charging the entire battery for a few minutes during this process. Specifically, when a cell is midway through being taken out of circuit, it can only be discharged, and would be dangerous to recharge. But a few minutes of downtime per year seems acceptable to me.

garbageman 3y ago

While it would be neat to build batteries that handle manufacturing defects akin to a CPU with 4 cores but 3 useable, I suspect the additional complexity, wiring, and circuitry is limiting. Batteries today are almost (or actually?) a commodity. Detecting and simply replacing the entire battery is probably cheaper and easier at grid scale.

londons_explore 3y ago
The wiring and complexity isn't very much - you simply need a contactor that can 'short' the offending set of cells. It only needs to close once, so can simply be made from a spring and meltable material. And you need ~100 of these per 400 volt battery. Beyond that, all the complexity is in software. Software needs to monitor cell voltages and currents to detect a self-heating cell. Software then needs to stop balancing that cell up (ie. let it discharge). At the moment the cell voltage hits zero, software needs to close the 'short' across the cell, permanently taking it out of the circuit. This design might occasionally prevent charging the entire battery for a few minutes during this process. Specifically, when a cell is midway through being taken out of circuit, it can only be discharged, and would be dangerous to recharge. But a few minutes of downtime per year seems acceptable to me.