鋰電網訊：2017年4月份，有部分Bolt EV的動力電池被報道出問題：“2017 Chevy Bolt EV battery may fail due to faulty cell; new pack needed for a few GM electric cars”，現在進一步擴大了，事情變得有些大條了。
部分2017年型號的Bolt EV電芯出現故障，當這個故障發生的時候，可能會導致車輛瞬間失去動力，沒辦法有效驅動，在高速道路上，這個事情可能會非常危險。這里有幾點值得考慮：
部分電芯的衰減比較快
部分電芯在后期會突然跳水
采取措施：通用汽車一直在通過其OnStar 的車輛網程序監控這個問題，通過車輛網收集電池的實時數據和BMS計算出來的電池的健康狀況，現在的問題是，車聯網本身追蹤也不能完全覆蓋所有的潛在失效，對于通用來說，Bolt的部分車型是個大問題。
有些廣告要給拿出來比一比，在某些情況下，非預設性的診斷覆蓋的東西，車聯網沒辦法。
如下圖所示，這是車主在車輛論壇里面吐槽
I've had the car for about 2 months now (Purchased 9/30) and today while driving on the freeway home I got a message saying Loss of Propulsion. I noticed that the car was only allowing around 30kwh of power to be discharged even when I mash the throttle down. I exit the freeway and proceed to try to make it home thinking I'd be able to make it as it's about a mile or so down the road. I come to a complete halt at a stop light and proceed to accelerate normally when the light turns green and I noticed the limit on battery discharging again and hit a max speed of around 45 miles an hour.
Stop for another red light and this time it is a big hill so I tried to accelerate as hard as possible to make it up the hill and I make it to about 30mph before the screen starts throwing up error messages and I notice my battery level go from around 40 miles(25% battery) down to 29 miles left and into the orange and then rapidly declining to 0 followed by more error messages of battery is drained and I am now stuck on the side of the road.
With 0 miles left and no drive to the wheels I do my best to pull over to the side and use OnStar to call for assistance. They call a tow truck which took about an hour to get there and now the car is sitting at the dealer because service isn't open. I sure hope it is dealt with quickly and a rental car provided.
Notes: Car was manufactured in August 2017 so if it is a battery failure that is certainly not a good sign for everyone with bolts older than that. Torontonian69 likes this.
從以上的現象來看，這個N2.1系列的電芯，反應還是真奇怪，一放電本身的特性就出現大問題，觸發BMS的故障，等恢復一加負載又跳水。這下損失可不小呢
When a cell "fails", its voltage tends to drop off very quickly, especially compared to other cells. Once the system detects the voltage of ANY SINGLE cell group is below minimum, it shuts down to protect the cells from over discharge. Obviously, if the battery is at 50% SOC and then suddenly a single cell drops to Vmin, then that cell is already damaged. This is why you get no warning. The new software must be more sensitive to detecting this. This is the equivalent of your phone shutting down during heavy use. I recommend anyone covered by this recall run your battery DOWN to 10% to maximize the chance of finding this fault. Staying at 90-100% SOC is not going to help the battery, but rather mask this problem.
電動汽車產業里面，這大概是第一個因為電芯問題，導致的召回，往前走，步步驚心，如履薄冰。成本還要降呢
根據“gmauthority.com”的消息，現在針對Bolt EV要啟動傳統汽車企業規模較大的一次OTA。電芯有問題，靠軟件來彌補，也會成為未來的常態。
General Motors has officially responded to reports of isolated battery cell failure in 2017 Chevrolet Bolt EV models. In response to the possible issue, the automaker will roll out a software update for Bolt EV that dealerships will perform free of charge.
GM told InsideEVs that the recall is not a safety recall, but asked that all owners participate in the software update. Some owners have reported battery cell failure that leaves the Bolt EV without drive power.
After analyzing OnStar data, GM noted the issue seems isolated to very early production units of Bolt EV. The automaker will continue to comb through its data and notify owners who may be at risk for battery cell failure.
The software update will introduce “additional warnings if a battery cell low voltage condition occurs, which could cause the vehicle to reduce or lose propulsion.” Owners will see an indicator light if the battery is at risk of cell failure.
The update will not fix bad battery cells. Additionally, starting at the end of this month, Chevrolet and GM will begin pushing over-the-air software updates to the Bolt EV. It will make the Bolt EV the first vehicle from GM to make use of a vehicle’s internet connection for seamless updates without having to visit a dealership.
論壇里面也發送相關的信息到了車主了：
Just got an email from GM titled “2017 Bolt EV Software Updates” and providing instructions for owner-initiated updates. Not going to reiterate the email here, but here is a like to the instructions: http://gmrecall.xert.net/publicimage...uctions_F2.pdf
這正好GM的SuSanta Sarkar和James Forsmark發表了《汽車電子自動化軟件更新OTA系統工程》，對于汽車電子來說，這將成為未來電動汽車廠家的標準配置，應對未來發生的問題。
汽車電子系統傳統上被設計為嵌入式分布式系統，主要在本地通信子網中廣播數據。這些系統由許多通過各種類型的通信網絡連接的電子控制單元（ECU）組成。傳統上，整車企業通過供應商來設計和構建這些ECU，然后承擔整合通信和驗證的責任。在此框架中，更新組件軟件需要連接外部工具和更新預期的ECU。這種方法存在以下問題：
?從供應商和性能角度來看，每個ECU的軟件更新都被視為一個獨立事件 ，因此在設計刷新軟件來說，供應商不會對自己的ECU刷新軟件要花多久設置考核，更不會把它作為一個關鍵參數。
?通常設計過程中，只考慮單個ECU的軟件更新，同時對多個ECU進行更新并沒有考慮過，多個ECU同時更新所需的通信網絡帶寬不受任何一個供應商的控制。
?ECU之間的軟件更新依賴性通常不明確。4S店經過培訓之后，修理技工可以使用手動錯誤檢測方法修補隱藏的依賴關系，在必要時安裝的其他軟件更新。
?有時為了保證系統的完整性，ECU的傳感器或執行器需要在軟件更新后進行手動操作一下
這篇文章，介紹了一下之前的事情，也提出了一種系統架構（Proposed Model of System Architecture）
系統架構可以考慮各種業務驅動因素來組織軟件體系結構和軟件元素。 由于車輛的生命周期通常在十年左右，因此軟件更新系統本身也是可更新的。 實現這一目標的系統方法是有一套明確的可能分離的軟件元素，并保證特意設計的接口不會隨時間而改變。 這種方法有助于一個軟件元素的變化不會影響整個系統。 軟件元素可以映射到一個或多個“對象”或“服務”
