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What would prevent the battery from having a segmented design so that multiple segments can be charged in parallel? Is there something about the chemistry that

What would prevent the battery from having a segmented design so that multiple segments can be charged in parallel? Is there something about the chemistry that requires the entire vehicle battery to be a single unit?

TylerE 9y ago
At some point the size of the connector TO the vehicle is going to be the limiting factor.
- techbubble 9y ago
  I was thinking of batteries connected in series with a mechanism to separate the connection during charging. The main connector would be the same. Perhaps this is just not possible with huge batteries? Edit: Oh I get it...the charging port is what you meant.
  - kumarvvr 9y ago
    Exactly my thought. Relays that connect the batteries in series for charging and reconnect in parallel for driving.
- andreyf 9y ago
  In the case of a truck, that seems less likely -- surely they could come up with a design that hooks in 2, 3, 10 plugs the moment the truck is ready to dock.
  - simonsarris 9y ago
    Their design has 4/8 ports: https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-Charging-Port-2.jpg https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-...
    - andreyf 9y ago
      Nice! I guess the width of the wires is the limiting factor? Or a cooling system? Regardless, curious to hear an informed analysis.
nimos 9y ago
That is how they work today. This is Tesla's current state of the art (larger) battery. As you might image in takes more than 1-2 to run a car. https://i.ytimg.com/vi/ga4L1w66AbU/maxresdefault.jpg https://i.ytimg.com/vi/ga4L1w66AbU/maxresdefault.jpg The problem is disgustingly parallel.
euyyn 9y ago
The battery is composed of cells connected in parallel and in series. Say P parallel strings of S cells connected in series each. You want your cells to be balanced: charged the same amount. You can charge every single cell individually, simultaneously, if you design your connections to support it. IIRC our packs were wired to charge the internal cells in pairs. If you think about it, though, with a given max current I = dQ/dt, you need the same amount of time to charge two cells each to a charge Q (mAh), no matter if you charge them simultaneously or one after the other. Because if you charge them simultaneously you can only supply I/2 each.

TylerE 9y ago

At some point the size of the connector TO the vehicle is going to be the limiting factor.

techbubble 9y ago
I was thinking of batteries connected in series with a mechanism to separate the connection during charging. The main connector would be the same. Perhaps this is just not possible with huge batteries? Edit: Oh I get it...the charging port is what you meant.
- kumarvvr 9y ago
  Exactly my thought. Relays that connect the batteries in series for charging and reconnect in parallel for driving.
andreyf 9y ago
In the case of a truck, that seems less likely -- surely they could come up with a design that hooks in 2, 3, 10 plugs the moment the truck is ready to dock.
- simonsarris 9y ago
  Their design has 4/8 ports: https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-Charging-Port-2.jpg https://insideevs.com/wp-content/uploads/2017/12/Tesla-Semi-...
  - andreyf 9y ago
    Nice! I guess the width of the wires is the limiting factor? Or a cooling system? Regardless, curious to hear an informed analysis.

nimos 9y ago

That is how they work today. This is Tesla's current state of the art (larger) battery. As you might image in takes more than 1-2 to run a car. https://i.ytimg.com/vi/ga4L1w66AbU/maxresdefault.jpg https://i.ytimg.com/vi/ga4L1w66AbU/maxresdefault.jpg The problem is disgustingly parallel.

euyyn 9y ago

The battery is composed of cells connected in parallel and in series. Say P parallel strings of S cells connected in series each. You want your cells to be balanced: charged the same amount. You can charge every single cell individually, simultaneously, if you design your connections to support it. IIRC our packs were wired to charge the internal cells in pairs. If you think about it, though, with a given max current I = dQ/dt, you need the same amount of time to charge two cells each to a charge Q (mAh), no matter if you charge them simultaneously or one after the other. Because if you charge them simultaneously you can only supply I/2 each.