Lithium Battery Woes

[flecc]

While most of our e-bike lithium battery troubles seem to have ended, these batteries continue to cause problems elsewhere, from fires on Boeing 787s to ever diminishing life promises in electric cars.

Now we learn that London's hybrid routemaster bus batteries are all failing, with over a hundred of the buses now running on their diesel engine only. That's a big problem since they are primarily an electric powered design, the relatively small 4.5 litre diesel output is intended only to generate battery charge and is inadequate for the large double decker's bulk. In consequence the drivers are struggling to keep up enough speed in traffic.

At least we are told that the batteries will be replaced under warranty. but that won't compensate the inconvenience.

I must say I'm baffled that they don't use sodium "salt" batteries, a proven and very reliable technology that's an ideal choice for e-vehicles that are in constant use seven days a week over long daily hours. Perhaps the desire to have the most advanced technology in the new routemaster affected the design choice of lithium, but I think it a rather silly choice for a near continuous use vehicle needing the highest degree of reliability.
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[trex]

the root problem may be that their diesel motor is not man enough, causing the battery to run low all the time.

 

[flecc]

Possibly, though they have said the fault is with the batteries. With Siemens involved in the design of the electrical system, I somehow doubt they'd have underrated, given their long e-transit experience.

Also there should be plenty of stationary charge time, given the frequency of stopping that London's buses have at almost all bus stops and drivers also doing the fare collection related duties.
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[OldBob1]

Maybe its all the extras add-ons like CCTV, satnav electric shaver socket and smartphone charger!!!! dragging the voltage down!!!! or should they bring back the trolley bus?

 

[anotherkiwi]

Possibly, though they have said the fault is with the batteries. With Siemens involved in the design of the electrical system, I somehow doubt they'd have underrated, given their long e-transit experience.

Ah ha! Siemens is involved, they are being punished by a greater force for preventing electric planes from crossing the channel!

 

[flecc]

should they bring back the trolley bus?

Wouldn't be a bad idea, though I think today's trams probably better. They'd both solve London's chronic particulate pollution problem.
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[anotherkiwi]

Crossing tram rails on a bicycle in the rain is a white knucke experience, I lived in Nantes for 30 years... Sometimes you can't cross the rails at 90°.

Trolly buses add visual pollution to the city with all those cables. There is a city experimenting with electric buses that recharge at each stop, can't remember where.

 

[jonathan75]

Also there should be plenty of stationary charge time, given the frequency of stopping that London's buses have
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Ah that's interesting - the hybrid buses which I'm familiar with in London automatically switch their engines off at idle. I think that's to get the co2 emissions down as far as poss. Could be undercharging as a result.

 

[trex]

Siemens try too hard to reduce CO2 emission, that's why the bus is sluggish.

 

[flecc]

Crossing tram rails on a bicycle in the rain is a white knucke experience, I lived in Nantes for 30 years... Sometimes you can't cross the rails at 90°.

Trolly buses add visual pollution to the city with all those cables. There is a city experimenting with electric buses that recharge at each stop, can't remember where.

I'm in a modern tram area so we are used to coping with the tramlines. Switzerland were first in with buses that recharged at stops, and they also pioneered a flywheel powered bus, the flywheel spun up to speed at each stop.
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[flecc]

Ah that's interesting - the hybrid buses which I'm familiar with in London automatically switch their engines off at idle. I think that's to get the co2 emissions down as far as poss. Could be undercharging as a result.

It would still surprise me if Siemens have undercalculated that, given their experience in this field. I think the statement blaming the batteries is the most likely answer, it's consistent with lithium introduction experiences elsewhere, taking two or more goes to get it right in each vehicle type.
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[flecc]

Siemens try too hard to reduce CO2 emission, that's why the bus is sluggish.

They aren't sluggish normally since the primary electric system is adequate. It's only when on the generator engine alone that they are sluggish with acceleration.
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[trex]

if these buses are partly recharged from the grid while operating then their critics will go away.

 

[flecc]

if these buses are partly recharged from the grid while operating then their critics will go away.

Well we'll see what happens when the replacement batteries are fitted.

With lithium batteries getting it wrong first time seems to be the norm. With e-bikes it took two replacement generations to get them satisfactory. Similarly with cars, in trying to get in early, Mitsubishi despite GM's help had to delay the electric version i-car launch four years running due to lithium battery problems during testing. And of course we know what happened when Boeing introduced new ones on the 787 Dreamliner.
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[SteveRuss]

I must say I'm baffled that they don't use sodium "salt" batteries, a proven and very reliable technology that's an ideal choice for e-vehicles that are in constant use seven days a week over long daily hours. .

Tell us about salt batteries flecc.

 

[flecc]

Tell us about salt batteries flecc.

Basically they use cheap and easily available sodium salts in a heated environment and run at around 240 to 350 degrees C in the later designs. This means they are best suited in applications with regular daily use, rather than intermittent, since maintaining their temperature during standby has a cost. They can be left to cool back to solid from molten and do not deteriorate in that state, but of course a restart would take heat up time first.

They've been used in delivery trucks and one UK courier ran a lengthy trial with a small fleet. Two of the earlier and still current e-cars, the Ford backed Think Car and the Smart ForTwo electric version both use sodium salt batteries and are supplied to regular commercial users.

You can see why they would suit a London bus, since they run around the clock seven days a week so standby heating would have little cost for them.

Online info is not bang up to date , but here's some links to the sodium battery technologies:

Link one

Link two

Link three

And for a rough summary of pros and cons, here's an extract from the Battery University article on them, it's within this page with no separate link to the item:

The rechargeable sodium-sulfur (NaS) gained worldwide attention during the 1970s and 1980s, but short service life and high cost dampened the enthusiasm. The sodium-nickel-chloride battery, also known as ZEBRA,* came to the rescue and today this battery is being used successfully in many applications.

ZEBRA has a nominal cell voltage of 2.58 volts and an specific energy of 90–120Wh/kg, a level comparable with Li-manganese and Li-phosphate. The service life is about eight years and 3,000 cycles. It can be fast-charged, is non-toxic and the raw materials are abundant and low-cost. ZEBRA batteries come in large sizes of 10kWh or higher and typical applications are forklifts, railways, ships, submarines and electric cars. A growing market for sodium-based batteries is load leveling, also known as grid storage. The Think City EV has a choice of ZEBRA and Li-ion. ZEBRA has advantages when operating at extreme temperatures and when the battery is in continuous use, such as in taxis and delivery vans.

The ZEBRA battery must be heated to 270–350°C (518–662°F), a temperature that is lower than the original sodium-sulfur battery. Even though special insulation minimizes heat loss, heating consumes 14 percent of the battery’s energy per day, which results in a self-discharge of 18 percent. An active ZEBRA battery should be on charge or in use. It takes 3–4 days to cool down, and reheating takes about two days depending on the SoC at time of shutdown. Common failures include electrical shorts due to corrosion of the insulators, which then become conductive, as well as growth of dendrites, which increases self-discharge.
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[Deleted member 4366]

They have silver cases. They give out 36v and have salt and lithium in them. What more do you want to know.

Talking of Siemens, the last time I flew to China, I sat next to guy that worked for Siemens. He was a member of a blue sky thinking team that investigated trends in energy, so he flew round the world looking at what was going on with every type of energy use, so that his team could inform Siemens where to concentrate their research and development. How do people get jobs like that?

 

[SteveRuss]

Wow. You learn a new thing every day apparently. Certainly true in this situation.

Thanks!!

 

[flecc]

They have silver cases. They give out 36v and have salt and lithium in them. What more do you want to know.

No lithium in them though, just sodium/nickel chloride, one of their advantages over lithium batteries.
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[Deleted member 4366]

Of course!! Derr!