一探究竟:特斯拉Model 3 电池系统

本文是一篇关于特斯拉Model 3 电池系统的拆解文章,及作者对Model 3技术的独特的理解和判断。
一直关注特斯拉技术的我,发现其中有一个我直接想过且很有创意的专利在Model 3实现了,所以我就连夜把这个文章复制到了我的云笔记里,顺便做了下简单翻译。

Model 3 电池包设计——一睹为快

With a starting price of $35,000, the Tesla Model 3 is half the price of the vehicles Tesla is used to designing and manufacturing, the automaker’s flagship Model S and Model X all-electric vehicles.

以35000美元起售价的Model 3 ,只有以往特斯拉Model S and Model X产品售价一半。

In order to achieve this more affordable price, Tesla had to design a whole new platform and battery pack architecture.
为了尽可能做到可承受价格,Tesla 设计了一款使用全新电池PACK结构的全新平台电动车。

Today, we get an exclusive first look at this new Model 3 battery pack architecture.
今天,我们拿到了一台新电池平台的Model 3。

We already know about the new battery cell format, which is arguably the main change. The cells in Model 3 are a different size than in Model S and Model X, which have cells known as “18 650” (18mm in diameter and 65mm long), while Model 3 has larger cells called “21 70” (21mm in diameter and 70mm long)”.
我们已经知道这款车使用了新电池单体规格,Model 3 使用的单体尺寸不同于 Model S and Model X所使用的“18650”规格。

The bigger cells enabled Tesla to optimize volumetric energy density.


Now Electrek obtained more details on the battery pack architecture built around those new cells.

The standard 50 kWh Model 3 battery pack is made of 2,976 of those cells in groups of 31 cells per “brick”. The bricks go into 4 separate modules (2 modules of 23 bricks and 2 modules of 25 bricks).That pack is going into production later this year.
标准50kwh的Model 3电池由2976颗电芯构成,每块模组使用了31只电芯并联,一共四个独立模组(其中2个由23串,2个25串 23*31*2+25*31*2=2976)这个新模组今年晚些时候进入量产。

Currently, Tesla is producing a 74 kWh ‘long range’ battery pack, which consists of 4416 cells in groups of 46 cells per brick and the same brick distribution in the 4 modules. Here’s a diagram of the distribution of the cells in a Model 3 battery pack:
目前,特斯拉正在生产74kwh长续航配置的电池包,这个电池包使用4个46P24S模组进行制作。下面是全新Model 3 的电池包图片:

That’s a big difference with the Model S and Model X battery pack architecture, which has several more modules per pack.
Tesla’s new 100 kWh pack, which is the top-of-the-line for Model S and Model X, has 16 modules with 516 cells for a total of 8,256 cells per pack. You can learn more about the Model S and Model X pack architecture here:
Teardown of new 100 kWh Tesla battery pack reveals new cooling system and 102 kWh capacity.
与Model S 和 Model X 更多模组最大的不同是这个心电池包只是用了少数几个模组。Model S 和Model X使用的电池包由16个模组,8256只电芯构成,关于100kwh系统可以去看链接。

That’s the main difference for the core architecture, but there are also several other more subtle changes that can give us some interesting insights into the new all-electric vehicles.

Unlike the Model S and Model X battery pack, Tesla didn’t make the Model 3 battery pack to be easily swappable. There are bolts, which are only accessible by removing trims from the interior of the car, that need to be removed in order to eject the pack.
It’s probably the last blow to Tesla’s battery swap station scheme, which was
put on the back burner last year.
不像Model S和 Model X的电池那样,特斯拉把Model 3的电池没有设计为更容易更换的结构。为了能够将电池包拆下来,有一些固定电池到车身上的螺丝必须从内饰中才可移除。这可能是特斯拉去年电池更换站计划的最后一击(没弄懂这句要描述的意思)。

Tesla’s battery swapping magic revealed in new patent application drawings

Another interesting point is that the Model 3 pack has no externally accessible high voltage connector other than the charge port, which kills the idea of an autonomous charging access point under the vehicle – something that Tesla has been working on: Tesla patent shows new way to automated high-speed charging with external cooling.
另一个有趣的一点是,Model 3没有的高电压连接器以外的充电端口,这也直接否认了Model 3 将会使用其外部冷却高速自动充电功能。

Tesla also designed the Model 3 battery pack to include the charger, fast-charge contactors, and DC-DC converter all in the same package. The packs also already have the necessary connectors for the upcoming all-wheel-drive dual motor option.

The automaker also incorporated some other ingenious designs to save weight and cost.
For example, it got rid of the external battery pack heater and instead, it heats the pack only using heat provided by the powertrain even when the car is parked.
Battery cells need to operate at a temperate core temperature in order to keep their optimal performance, which means that they need to be cooled in warm conditions and heated in cold weather.


Waste heat from the powertrain can be used when the car is moving, but Tesla designed a thermal controller for Model 3 that can also use heat from the powertrain even when the vehicle is parked, like at a Supercharger for example, which is important since the charge rate drops if the battery pack is too cold.
Even when parked, Tesla’s software can send a request to the powertrain inverter to start powering up and pass the appropriate currents to the motor in order to produce enough heat to warm the cells – all while not producing any torque so the Model 3 doesn’t move.
Tesla apparently judged the system efficient enough to not include an external battery pack heater in the Model 3 and replaced it virtually entirely through software.


Finally for the more inside baseball stuff, here are the main electronic components of the battery pack:

1. Charge port connector 充电连接器
2. Fast charge contactor assembly 快充集成件
3. Coolant line to PCS (PCS冷却管)
4. PCS – Power Conversion System (功率转换器)
5. HVC – High Voltage Controller 高压控制盒
6. Low voltage connector to HVC from the vehicle
7. 12V output from PCS
8. Positive HV power switch
9. Coolant line to PCS
10. HV connector to cabin heater and compressor
11. Cabin heater, compressor and PCS DC output fuse
12. HV connector to rear drive unit
13. HV pyro fuse
15. HV connector to front drive unit
16.Negative HV power switch
17. Connector for 3 phase AC charging

以下为我对Model 3 技术的一个粗浅的理解和判断。


特斯拉到目前为止还没有正式将他超级工厂 Gigafactory 生产的21700电芯应用在目前的Model 3产品上,文章也提到了,这个电芯将会在2017年的晚些时候进行量产,说明Gigafactory 的一致性、良品率等等方面还没有做好。电池产品的开发是一个长周期的工作,不可能一蹴而就。所以回过头看中国2015-2016年疯狂的扩产投资,到现在已经在逐步放量了。虽然国内的车企、电池众多,能够上规模的配套厂也有限。而那些没有和整车共同开发配套的中小型电池厂将会在2017年四季度——2018年初这段时间内逐步爆发结构性的产能过剩。

根据前期的报道,model3 将会使用21700电芯,相对于18650电芯,体积稍微增加了一点,但却带来了大约25%的能量提升,这给电动汽车电池设计带来足够多的进步。国内力神、亿纬锂能等大厂前期扩产能的时候就已经以21700作为规划,所以现在看来产能过剩的风险不大。CATL和国轩高科、赣州孚能这些大厂有主机厂源源不断的订单支持,也不会产能过剩。但中国200家电池生产商,前期盲目上马的这些电池厂今后将会面临比较大的产能消耗压力。


从上述文章我们也能看出来,现在Model 3 的定位是一款廉价版的纯电动汽车,相比它的大哥Model S和Model X ,老三的电池电量变少了,四驱变两驱了,电池包也不再集成到车底盘上了,甚至是电池的热管理系统都取消掉了,为了满足加热需求,电池包采用了新的电机余热进行加热(这个专利想象很棒,但是热效率应该不大)。同时车身进行了风阻优化,使用了一个18寸的空气动力学轮毂(据说单单轮毂技术就可以带来5%以上的续航,只是太丑了,客户不买账。)





Electrek网站推出了一篇他们关于特斯拉Model 3 的拆解文章:
Tesla Model 3: Exclusive first look at Tesla’s new battery pack architecture

  • 电动汽车
  • Model3
  • 电池





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