Charger / balancer co-design

In the process of upgrading one EV (lead acid-based) and planning a second (LiFePO4-based), I've spent a lot of time pondering the questions of charging and balancing the cells. I've come to the conclusion that these are not separate tasks. So I find it unusual in the EV community that the two topics are treated so separately. You buy your charger from company X, and then your balancers from company Y, and you pray that they play nice together.

Your charger comes pre-configured with a charge profile from the factory, and the balancer boards have the unsavory job of trying to fight against that charge profile to get all the batteries charged before the charger shuts off. What's going on here? I seem to be missing something.

Another possibility... which is the system being used on the lead acid EV I'm upgrading... is to install separate chargers on every battery. This is very practical if you only have 10 batteries to charge, and don't have to worry too much about discharge characteristics. But when you get into LiFePO4 territory, now you're talking about 45, 50, 90, 100 cells to charge individually? And still need a protection mechanism to protect them as they discharge? It seems like there must be some economies of scale that would be missed by installing separate chargers on every cell.

Yet, in many ways, having each cell charge individually is the ideal.

How can that ideal be accomplished with a series charger and balancer boards? What if the individual cell balancers know the charge profile of the cells, and direct the charging at a local level? The "charger" would become a slave unit, a cooperative partner that provides the total voltage requested right now by the balancers in the pack, with the current limited by the smallest current any single cell needs + the maximum current a balancer board can shunt (after some of them start ramping down).

So, it would be like you split the charger in half. Put "the dumb half" that has the AC windings and the DC regulator in a common spot, and spread "the smart half" that knows the charge profile out to each battery as part of the balancers. The dumb half shouldn't really be dumb... it should be Power Factor Corrected for efficiency, and it should actually be pretty sophisticated with tight control over the voltage and current being supplied to the pack. And the smart half could be pretty simple, using the simplest circuitry available to conduct CC/CV/float charging on a 3.2V cell.

The feedback from all those balancer boards to the charger base is the really tricky part in this equation, to make charging reliable and robust. I don't have a good suggestion there yet. I've been playing in my mind with differential op-amps, and wondering if they'd be sensitive enough to get it right without wandering off into wild oscillations or positive feedback loops.

Are there any chargers out there right now that match this design philosophy? I have heard suggestions that perhaps the Manzanita chargers do this, but their website is very "least common denominator" in this respect. About their chargers, the Manzanita website says (and I quote), "The actual power delivered is a function of input and output voltage." Whereas I'd like to see something that says, "The actual power delivered is a function of input and output voltage, the needs of the individual cells as they charge, and the capabilities of the balancer boards."