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.

更大的单体尺寸,使得Tesla得以最大限度优化电池的能量密度。


Now Electrek obtained more details on the battery pack architecture built around those new cells.
现在Electrek获得更多关于使用新电芯的Pack结构细节。

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.
这款全新纯电动汽车的电池在架构方面的不同是其最大的差异,但是也有一些微妙改变能给我们提供有趣的观察。




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.
特斯拉还把电池组的充电器,快速充电接触器和DCDC变换器都设计在同一个包内。电池包也预留了具备必要的连接器为即将到来的全轮驱动双电机的选择。

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.

特斯拉也做了其他一些节省重量和成本的巧妙设计。例如,它去掉了外置电池组加热器,而只使用汽车动力总成提供的热量,即使汽车停了下来,也能使电池发热。电池需要在一个温和的核心温度下工作,以保持其最佳性能,这意味着它们需要在温暖的环境下冷却,在寒冷的天气下加热。

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.

当车移动时,动力系统的余热可以进行利用,但特斯拉为毛豆3设计的温度控制器也可以从动力热,一个很重要的原因是防止停车时,如果电池过冷导致的充电倍率下降。
即使在停车时,特斯拉的软件也可以向动力总成逆变器发出一个请求,启动电源并将适当的电流传递给电机,以产生足够的热量使电池发热,但不能产生任何扭矩,车辆不产生移动。
特斯拉毛豆3显然能够完全通过软件使系统足够高效的电池包外部加热。

Finally for the more inside baseball stuff, here are the main electronic components of the battery pack:
最后是电池包内部的元器件基本布置。


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。

1、能量提升导致的产能过剩。

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。

2、产品力=好的设计+成本控制

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。)

综上几点,我认为特斯拉进行了很大的降本设计,不单单是把电池电量由原来的100kwh降到50kwh(50%的降幅),在整车重量、电机方面,车身动力学方面都做了新的技术方案。而且通过一系列优化,使用50kwh电量依然还能带来300km左右的续航(百公里能耗大约17kwh,和目前国内的电动车差不太多)。而3.5万美元(约22万人民币)的起售价,在美国政府也有大约1万美金的两级补贴这样的价格,买一辆300km续航的明星电动车,在国际市场上来看,都是极具竞争力的。

3、专利的落地——打造产品竞争力的最佳法宝

国内的专利太多不具有真正的意义,或者或实现量产的可能性太小,因为本身这些专利技术就很鸡肋。我们可以看到特斯拉申请的专利很新鲜,但是细细一想这些不是我们想不到,而是我们的专利太难落地。很多学校、科研机构有很多不错的专利,但是苦于没有市场应用,所以导致了技术进步的步伐不如别人。这几年随着资本的大量涌入新能源汽车行业,我们也能够看到越来越多的新能源汽车技术被应用,大量的专利在不断地落地产生价值。

特斯拉使用电机余热对电池系统加热这个专利,我们不能说这是脑洞大开的想法,且不说这个技术的有效性如何,但人家真正把这些想法用产品的形式做出来了。这是值得我们中国汽车工程师学习的。

国外
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


相关标签:
  • 电动汽车
  • Model3
  • 电池

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哩小熊

新能源汽车从业者,电动汽车.项目经理,混合动力汽车.硬件工程师,目前在主机厂担任纯电动乘用车电池产品经理。先后做过混合动力总成项目、电动助力转向系统、60kw电机控制器项目、6-8米纯电动中巴车整车项目。研究方向:新能源汽车/电池/电机/电控/智能汽车等。

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