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[quote author=2IDSGT]More evidence that the battery's design/manufacture is fundamentally flawed.

At the moment that's more evidence that the battery doesn't follow the same design paradigm as the Tesla's batteries, than evidence of a fatal flaw. It may be Boeing/Yuasa intended the risk to be addressed by some other mechanism, there isn't sufficient data to make a conclusive judgement (especially for those of us who aren't Lithium-Ion battery engineers).

To quote a famous saying on the relation of reality and models: 'the map is not the territory'. I've no background on 787, but 777 hit us with a bunch of surprises in flight-test (and service) that just hadn't come up in all the modelling and iron-bird testing done before the flight-test campaign. I was only paying attention to the Primary Flight Control System stuff, and only seeing what made it across the Pond (the 777 PFCS was developed by BAE Rochester), but just from memory we had some fairly spectacular stall behaviour ('I'm too old for this shit' to quote the PFCS flight test engineer after it flick-rolled 70 degrees right yet again), some markedly long landings at Edwards Air Force Base, and even after it was certified and in service, 'tail-wag' that was regularly making the passengers at the rear of cattle-class airsick. That's not counting the daily tweaking of flight-control laws that had been expected, nor, straying outside of PFCS territory, not one, but two decompression emergencies, at least one of which hospitalized some of the flight-test crew. And yet testing and modelling on 777 was supposed to have reached previously unseen levels of fidelity with real-world behaviour. And, after all that, both the 777 hull-losses to date were due to completely unexpected phenomena - ice crystals blocking the fuel heat-exchanger in the Heathrow crash and a short through the pilot's oxygen hose in the Cairo fire - with the ice-crystal issue taking considerable research to pin down and the oxygen hose short hypothesized rather than proved.

Boeing will already have at least one battery test-rig in the form of the iron-bird for the electrical systems, possibly more depending on how they set up ground testing and integration. While an engineering rig could be built to simulate the operation cycle for the batteries across multiple battery systems at a time, a massive problem arises if it doesn't replicate the mechanism that's actually causing the problem, and we don't know precisely what that is yet. Attention is focussing on dendrite formation shorting out the batteries, but we haven't had that confirmed, we don't know why some batteries are affected and others aren't (cycles? cycle length? pressure, temperature, whatever) and we don't know why it's happening in the Yuasa batteries when it will have been one of the failure modes looked at. Test-flying the 787 will let Boeing conduct more rigorous measurement of every parameter they think may be relevant in order to a) feed back into the failure investigation programme, and b) contribute to any test rig design. I wouldn't be surprised to find the battery cells are being MRI-scanned before and after each flight to monitor their internal condition.

Airbus announced Friday they're dropping Li-Ion for the A350 and reverting to Ni-Cad. Even if they're confident in the technology, the risk of a knee-jerk ban by regulators probably makes that a sensible decision. http://www.reuters.com/article/2013/02/15/airbus-battery-idUSL5N0BF1S720130215

(Ironically my car's lead-acid battery failed a couple of weeks ago during the cold-snap, it's a Yuasa )

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<blockquote data-quote="DWG" data-source="post: 177216" data-attributes="member: 414">[quote author=2IDSGT]More evidence that the battery's design/manufacture is fundamentally flawed.</blockquote>At the moment that's more evidence that the battery doesn't follow the same design paradigm as the Tesla's batteries, than evidence of a fatal flaw. It may be Boeing/Yuasa intended the risk to be addressed by some other mechanism, there isn't sufficient data to make a conclusive judgement (especially for those of us who aren't Lithium-Ion battery engineers).To quote a famous saying on the relation of reality and models: 'the map is not the territory'. I've no background on 787, but 777 hit us with a bunch of surprises in flight-test (and service) that just hadn't come up in all the modelling and iron-bird testing done before the flight-test campaign. I was only paying attention to the Primary Flight Control System stuff, and only seeing what made it across the Pond (the 777 PFCS was developed by BAE Rochester), but just from memory we had some fairly spectacular stall behaviour ('I'm too old for this shit' to quote the PFCS flight test engineer after it flick-rolled 70 degrees right yet again), some markedly long landings at Edwards Air Force Base, and even after it was certified and in service, 'tail-wag' that was regularly making the passengers at the rear of cattle-class airsick. That's not counting the daily tweaking of flight-control laws that had been expected, nor, straying outside of PFCS territory, not one, but two decompression emergencies, at least one of which hospitalized some of the flight-test crew. And yet testing and modelling on 777 was supposed to have reached previously unseen levels of fidelity with real-world behaviour. And, after all that,&nbsp; both the 777 hull-losses to date were due to completely unexpected phenomena - ice crystals blocking the fuel heat-exchanger in the Heathrow crash and a short through the pilot's oxygen hose in the Cairo fire - with the ice-crystal issue taking considerable research to pin down and the oxygen hose short hypothesized rather than proved.&nbsp;Boeing will already have at least one battery test-rig in the form of the iron-bird for the electrical systems, possibly more depending on how they set up ground testing and integration. While an engineering rig could be built to simulate the operation cycle for the batteries across multiple battery systems at a time, a massive problem arises if it doesn't replicate the mechanism that's actually causing the problem, and we don't know precisely what that is yet. Attention is focussing on dendrite formation shorting out the batteries, but we haven't had that confirmed, we don't know why some batteries are affected and others aren't (cycles? cycle length? pressure, temperature, whatever) and we don't know why it's happening in the Yuasa batteries when it will have been one of the failure modes looked at. Test-flying the 787 will let Boeing conduct more rigorous measurement of every parameter they think may be relevant in order to a) feed back into the failure investigation programme, and b) contribute to any test rig design. I wouldn't be surprised to find the battery cells are being MRI-scanned before and after each flight to monitor their internal condition.&nbsp;Airbus announced Friday they're dropping Li-Ion for the A350 and reverting to Ni-Cad. Even if they're confident in the technology, the risk of a knee-jerk ban by regulators probably makes that a sensible decision. <a href="http://www.reuters.com/article/2013/02/15/airbus-battery-idUSL5N0BF1S720130215" target="_blank">http://www.reuters.com/article/2013/02/15/airbus-battery-idUSL5N0BF1S720130215</a>&nbsp;(Ironically my car's lead-acid battery failed a couple of weeks ago during the cold-snap, it's a Yuasa <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink&nbsp; &nbsp; ;)" loading="lazy" data-shortname=";)" /> )[/QUOTE]

[QUOTE="DWG, post: 177216, member: 414"] [quote author=2IDSGT]More evidence that the battery's design/manufacture is fundamentally flawed. [/quote] At the moment that's more evidence that the battery doesn't follow the same design paradigm as the Tesla's batteries, than evidence of a fatal flaw. It may be Boeing/Yuasa intended the risk to be addressed by some other mechanism, there isn't sufficient data to make a conclusive judgement (especially for those of us who aren't Lithium-Ion battery engineers). To quote a famous saying on the relation of reality and models: 'the map is not the territory'. I've no background on 787, but 777 hit us with a bunch of surprises in flight-test (and service) that just hadn't come up in all the modelling and iron-bird testing done before the flight-test campaign. I was only paying attention to the Primary Flight Control System stuff, and only seeing what made it across the Pond (the 777 PFCS was developed by BAE Rochester), but just from memory we had some fairly spectacular stall behaviour ('I'm too old for this shit' to quote the PFCS flight test engineer after it flick-rolled 70 degrees right yet again), some markedly long landings at Edwards Air Force Base, and even after it was certified and in service, 'tail-wag' that was regularly making the passengers at the rear of cattle-class airsick. That's not counting the daily tweaking of flight-control laws that had been expected, nor, straying outside of PFCS territory, not one, but two decompression emergencies, at least one of which hospitalized some of the flight-test crew. And yet testing and modelling on 777 was supposed to have reached previously unseen levels of fidelity with real-world behaviour. And, after all that, both the 777 hull-losses to date were due to completely unexpected phenomena - ice crystals blocking the fuel heat-exchanger in the Heathrow crash and a short through the pilot's oxygen hose in the Cairo fire - with the ice-crystal issue taking considerable research to pin down and the oxygen hose short hypothesized rather than proved. Boeing will already have at least one battery test-rig in the form of the iron-bird for the electrical systems, possibly more depending on how they set up ground testing and integration. While an engineering rig could be built to simulate the operation cycle for the batteries across multiple battery systems at a time, a massive problem arises if it doesn't replicate the mechanism that's actually causing the problem, and we don't know precisely what that is yet. Attention is focussing on dendrite formation shorting out the batteries, but we haven't had that confirmed, we don't know why some batteries are affected and others aren't (cycles? cycle length? pressure, temperature, whatever) and we don't know why it's happening in the Yuasa batteries when it will have been one of the failure modes looked at. Test-flying the 787 will let Boeing conduct more rigorous measurement of every parameter they think may be relevant in order to a) feed back into the failure investigation programme, and b) contribute to any test rig design. I wouldn't be surprised to find the battery cells are being MRI-scanned before and after each flight to monitor their internal condition. Airbus announced Friday they're dropping Li-Ion for the A350 and reverting to Ni-Cad. Even if they're confident in the technology, the risk of a knee-jerk ban by regulators probably makes that a sensible decision. [url=http://www.reuters.com/article/2013/02/15/airbus-battery-idUSL5N0BF1S720130215]http://www.reuters.com/article/2013/02/15/airbus-battery-idUSL5N0BF1S720130215[/url] (Ironically my car's lead-acid battery failed a couple of weeks ago during the cold-snap, it's a Yuasa ;) ) [/QUOTE]

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