昨天晚上和宋哥等聊天，聊起了他的新项目做电池材料轻量化，上盖和底盖材料，密度1.4啥的。我不是学这块的，不过一晚上睡不踏实，来整理一下这块的内容，也要跟上时代的潮流。

我对电池包的材料认知来自于这篇文章《Voltec Battery Design and Manufacturing》，里面叙述了设计的要求，其实电池按照模组形式搁在包里面，需要做的结构工作挺大一个事。

1）钢

下盖：简单来说就是承重，防火烧，汽车结构和材料工程师第一选择用钢嘛    

The battery tray was designed as the backbone of the RESS battery.

The design needed to be structurally sound to be able to carry the 140kg weight of the battery sections, and to tie in as an integral part of the vehicle structure. After researching various materials for the tray, steel was chosen as the material due to its stiffness and strength advantages.

上盖：要轻、要防火（温度隔离）、防水和电磁屏蔽

cover  made of a sheet molded compound.

The cover's primary duty is to resist any foreign body or liquid from entering the pack.

A silicone seal on the cover also seals the cover to the battery tray.

The pack's exterior is covered by a heat reflecting aluminum foil (modified polyethylene copolymer film with scrim reinforcement).

The need for insulation was driven by specific performance requirements for the exposure temperature for the lithium ion battery cells and was further defined by limited packaging space.

2）铝

   这个我们以麦格纳现在给三星买走的部分来分析这个转变，用铸铝

 I3 里面的结构件26.1kg，老大哥铝盖子，其实很轻的

 这个Model S其实更深入到底盘部件去了

3）其他材料

  这个是在现代和LG化学在搞的事，用复合材料做底盖和上盖，其基本是想把35KG的下盖20kg+2去了.

  从材料特性，我们也是只能从定性的分析来粗略判断和对比

 也有不少公司拿着开始做对标

    我个人的感觉，铝和钢可能还是主流，特别是下盖，你仔细看看LEAF下一代样品用的LGC的电池模组做的60KWH的电池车，用这些撑不住不住啊，本来上盖的选择就多了。

小结：

1）其实电池包底盖设计，算是最为核心的结构设计点之一了，材料选取要满足的内容，写个几十页的需求随随便便的

2）用在大巴啥的，可能更好一些，不过总体来说，铸铝更实在一些，特别是与车体连接性，考虑材料也是系统性考虑之一