BYD Electric Motor Teardown | Full Engineering Analysis by Munro

Hi, welcome to Monroe Live. I'm Paul

Turbull >> and I'm Matthew Lawrence.

>> We're here today to talk about this BYD motor. But first, a little background on

motor. But first, a little background on Monroe and Associates. We're uh an engineering consulting firm that helps our clients beat the competition by

number one knowing what the competition is doing and number two implementing lean design principles to improve their designs and get ahead. This is one of

the key competitors out there right now.

BYD is the big player in the EV market and um hybrid market right now in China.

And there's been a lot of talk about how they are moving ahead of the European and US competitors.

And so we're going to take apart, this is one of their latest motors. We took

apart an older version um not too long ago from the Skywell and found that uh this this particular one has a lot in

common with their their older one. Um,

so it's a um a pretty compact unit. Um,

how many kilowatts is it?

>> So, this motor is 183 and I think the torque is about 330 Nm, >> which is about the same as it was before, but um this only weighs um 84

kg.

Um, and so it's in a tight package, smaller, lighter. Um,

smaller, lighter. Um, it's the IDM210.

And to 210 refers to the diameter, the stator inside the the motor housing. And

it's a part of a new family of motors that BYD is is coming out with. It's

going into the the Han, the Tang, and the Tang L. The Han is a a performance

sedan, and the Tang is a SUV, and the Tang L is a seven passenger SUV. And

this is the rear drive unit for th for those for the mainline version of this, the mainstream version. Um they have a higher performance version of this that

does I think almost 500 kilowatts. So

we're going to have a quick look at what's going on inside.

All right. First of all, it's quite clear we got Borg Warner's name is all over this. This is a BYD

drive unit, but uh clearly Borg Warner is the supplier for this. and uh um they've done a fantastic job. We keep

seeing incremental improvements. Um one of the

incremental improvements. Um one of the things that we're it's nice to see is the improvement in the um water. So this is where the water

um water. So this is where the water passes from the inverter into the motor and this connection is automatically made when the inverter comes down. But,

uh, the seal system here, uh, has a a face seal on the top and a O-ring around the

around this part that goes inside. And

so, the double seal is to try to keep regardless of thermal expansion and over time >> orientation >> orientation, it'll always uh, keep that

seal. uh which is critical. We don't

seal. uh which is critical. We don't

want water leaking out anywhere.

So that's all nice. One of the a couple things that saw over here when we did the uh p pulled off this cover is that

these um connections to the motor are flexible. They used a stranded wire to

flexible. They used a stranded wire to make this this connection and that uh makes assembly a lot easier to make sure that it will

You can move the parts in >> tolerances, >> but it does cause some issues because uh now vi over vibration this flexible lead

can uh has to be supported to make sure that you don't have um electrical connection failure down in there. And a

connection failure at the three-phase connection of a motor like this is a catastrophe. So, um it's really

catastrophe. So, um it's really important to keep all this stuff well supported.

All right. It's a

12.83 to1 ratio is what they were told. And

which is an unusually high gear ratio, which means it's a real fast spinning motor. Uh close to 18,000 RPM.

motor. Uh close to 18,000 RPM.

And uh we got uh roller bearings for the lay shaft. This is the lay shaft. So

lay shaft. This is the lay shaft. So

input shaft, lay shaft and the output.

Large number of gear teeth on the on the output and uh big difference between the number of gear teeth on the input and the on the lay shaft.

relatively small deer teeth, which is one of the things that's enabled by the 330 Nton meters of torque, which is

relatively low for a rear drive unit.

And there it is. There's the resolver.

Uh, one thing that's nice, sometimes companies will put um adjustment mechanisms in there, so slotted uh screw holes to allow them to tweak it. This is

solidly mounted with no adjustment, no mechanical adjustment, which implies that they use uh software to um adjust the >> virtually. Yeah.

>> virtually. Yeah.

>> All right, we're going to open up the inverter now. It has 21 screws, two of

inverter now. It has 21 screws, two of which were security bits, so we went and uh took those out already. I'll put on

some gloves and uh get rolling.

Here we go.

The DC power comes from the battery. It

comes in here. It goes through this.

This is a filter that uh filters out some of the switching ripple. The

switching comes from the switches. This

is the control board for the switches.

And then underneath this are the switches, the um >> MOSFETs.

>> They're either MOSFETs or IGBTs. And at

this point, we can't see enough of them to know that which way. This is the capacitor.

Um they've got 510 microfarads of capacitance. It's showing it's a 750

capacitance. It's showing it's a 750 volt DC capacitor.

Um and then the three-phase power then comes from so it's DC coming in here and then three-phase AC coming going out

here uh through this. This is the current set of current sensors. Um,

since it's all one block, I can't tell whether they're using two or three current sensors.

>> It It looks like three, like >> like all three of the the currents are being measured.

>> Yeah.

>> Um Tesla just does two, other companies do three. It's a you only really need two

three. It's a you only really need two to do the control, but knowing the third

gives you a way of uh detecting faults.

And so it's a relatively inexpensive way to detect faults um that are um not detectable any other way. uh although

Tesla uses uh some clever software algorithms to try to get that fault detection with just two.

Um, so this is a rather interesting um, uh, filtering arrangement and, uh, we're going to want to take a little closer

look at that. Uh, this can help with, um, uh, reducing the EMI noise and it also helps with

reducing bearing currents and loss in the motor. uh when you filter the the DC

the motor. uh when you filter the the DC coming into the um so >> it's like a fite choke or >> yes uh like a fite choke but uh they

usually use a little different material for that because the power is so much higher. Um you'll see kind of a fite

higher. Um you'll see kind of a fite choke on like your laptop power supply that kind of thing. It's the same idea but amped up to uh

>> 400 plus.

>> Yeah. Thousands of watts.

>> Yeah. Under this board. When we take this apart, then uh there's the the cooling for it. But uh you can see the water comes on in here.

>> Passes through the uh the heat the >> switching board.

>> Yeah. Underneath the switches where most of the heat is taking place. and then

then leaves here and goes into the motor.

One of the things we like is there's just one big casting. The castings are expensive. Uh and

expensive. Uh and um everything else is done. The two the top and bottom covers are just stampings

uh which are significantly less expensive at um the appropriate uh volumes. So at 150,000 volume that

uh volumes. So at 150,000 volume that this is is produced at maybe more if they're using this in other vehicles um then these stampings are going to

save them quite a bit of money. All

right, we have the uh BYYD Borg Warner motor all torn apart here.

And so I'm going to go part by part and tell you a little bit about what we see at Monroe and Associates in this kind of

a assembly. As we already mentioned that

a assembly. As we already mentioned that it's on the surface a very standard looking um

electric drive unit. It's uh well over 200 horsepower type of drive unit and it's in this drive unit is used in um

mainstream electric vehicles uh a midsize SUV and a sedan um for the China market.

Uh it's a high volume application and we we're seeing sort of a convergence of every automaker arriving at kind of the

same looking drive unit um across the board with uh two-stage gear reduction,

a bar wound stator and a interior magnet PM machine with the inverter closely integrated in with the housing of the of

the motor all kind of together as one unit. And that's proved to be an

unit. And that's proved to be an extremely cost-effective way of doing a powertrain for an electric vehicle. This

is also used in their um their hybrid application. They kind of have an

application. They kind of have an extended range electric type hybrid uh that they use this powertrain for.

So, I'm going to go ahead and start here at the back end of the of the motor. So,

this is the the rear cover of the motor.

In it, the the inverter is mounted on top and it passes the three-phase connections through here into the stator. Um, but what I want to really

stator. Um, but what I want to really focus on here is this back section. um

that provides a mounting spot for their resolver.

So the resolver fits down in here.

This tells the machine, the controls the position of the rotor. And I like this resolver because it's really small and

uh inexpensive. Fits right down in here.

uh inexpensive. Fits right down in here.

It has no shielding on it and it doesn't need shielding because it's in this aluminum pocket in the back of the motor

isolated from the high power um and and strong fields of the motor. So nice

pocket for the uh resolver. Also, if you look down inside there, you see this this brush thing. It's a uh these are

carbon fiber brush that touches the shaft and that helps dissipate any static electricity and also high

frequency electricity that ends up being generated in the shaft by the action of the switching um in the stator. So you

have the stator that transmits power to the rotor and it also ends up generating a little bit of electricity in the rotor shaft which can build up and if you don't do something like that then it

will tend to arc produce electricity arcs that arc across the bearing. This

is the rear bearing for the the motor that fits into that location. And this

by the way is the resolver rotor. So

this is what goes into that back end of the machine. And then this the outside

the machine. And then this the outside part of this bearing the um outer diameter

um fits in here loose fit that um where the tolerances are taken up by these two O-rings. So there these allow a little

O-rings. So there these allow a little bit of compression and they keep the outer race of the bearing uh steady while it's in here. and it

allows for nice easy slip fit assembly.

Um, but if you look carefully at this insert, this is inserted into the casting during the casting process. Um,

it's not your typical steel. Um, you

like to have steel on steel for your bearing mount because the aluminum when it gets hot, it expands at a faster rate

than the aluminum than the steel of the of the ro the bearings. And so having steel here eliminates that um difference

in expansion rate. So the fit stays perfect overall temperatures. But this

is actually coated with a material that makes this um very low conductivity electrical conductivity. So it isolates

electrical conductivity. So it isolates the bearing from the electrical uh voltage that's generated by the

action of the motor. And so instead of having the electricity generated by the motor going through the bearing, it has

an easier path going through the brush the brushes here um from the from the rotor. So we have a the housing and the

rotor. So we have a the housing and the rotor end up being at the same electrical potential and you don't end up with u bearing wear

due to bearing currents. So this is a nice solution. It's not cheap. This, you

nice solution. It's not cheap. This, you

know, this component costs a little bit of extra money and this special insert cost a little bit of extra money, but it's much cheaper because they can use a

standard bearing here. It's much cheaper than using ceramic ball bearings um than uh so that some other companies

use and other methods for um like for example a uh a a carbon brush that sits on here. Um so other methods are more

on here. Um so other methods are more expensive than this. So, it's a cost-effective way to eliminate a

failure mode and it's something that um BYD has some experience with. Uh but

also Borg Warner offers this kind of solution. Um and it's the kind of thing

solution. Um and it's the kind of thing that a company that has been in the electric drive unit business for a long time um can offer their customers. And

Borg Warner is a good example of that.

um you don't if you notice but uh you know so we see uh Borg Warner is on all of these. So BYD has contracted with

of these. So BYD has contracted with Borg Warner to manufacture this um drive unit to their specifications

and BYD is going to specify a motor that is a little bit different than for their China applications a little bit different than what Borg Warner would

offer to say for example a North American or a European customer. Um and

and a good example of that is um the water cooling.

So in the China market um water cooling is an except exceptionally uh cost-effective method for cooling the

motor. Um the downside of water cooling

motor. Um the downside of water cooling is it cools the stator very nicely but it does absolutely nothing to cool the

rotor. Uh, so the rotor ends up just

rotor. Uh, so the rotor ends up just roasting um and that puts a lot of pressure on the magnet. So the magnets

end up um potentially could demagnetize um because they get hot when you're at under extreme conditions.

For the China market, that's not really a problem because they can have rare earth magnets that have as much dprosium and turbium in them as they need to give

make the magnets impervious to high temperature. So in the China market,

temperature. So in the China market, water cooling and not cooling the rotor is a good option for the rest of the

world where heavy rare earth elements are difficult to get a hold of and high power permanent magnets um are represent

a supply chain risk. Usually we want to oil cool to make sure that the rotor can be cooled and the temperature of the rotor is managed so that we can use

magnets that don't contain the heavy rare earth elements. So one different solutions for different applications and different markets and this is something

that you know multinational corporations like Borg Warner are able to offer and customize for their their uh applications and their customers.

So water cooling what the big problem with water cooling is the potential for leaks. I did a

review of one of BYD's earlier motors that showed evidence of some lastminute engineering to fix potential

leak issues on the water cooling.

Typically, you'll have either an extrusion here that has hollow passages for the water um and then you have to seal on both

sides of the extrusion. So the extrusion goes to casting um and you have to try to seal those the the top and bottom

with RTV and that's where uh BYD previously on their previous design had some issues and had to do some design

changes and we did made a previous video about that. Here they took the inner and

about that. Here they took the inner and outer housing both cast material. So

they cast an inner housing and they cast an outer housing and then they use stir friction stir welding to weld it together on the top and down at the

bottom. And then they come back and they

bottom. And then they come back and they machine the surface so it's utterly seamless and hermetically sealed. So

there is no chance for a leak. There's

no O-ring seals between the two housings that could become damaged and leak. Um

so this is an excellent solution uh kind of bulletproof solution for producing a leakp proof water cooled motor. Um and

it's a unique right now uh in the industry. I'm I'm really happy to see

industry. I'm I'm really happy to see this uh Borg Warner has a has a fantastic solution for uh water cooled market water cooled motor for the China

market. Um, it's a also relatively

market. Um, it's a also relatively inexpensive process. But having said

inexpensive process. But having said that, it's not super cheap to make machined castings, one that fits inside

the other with these clever little fins on the old on the outside of the inner casting to produce great heat transfer and then friction stir weld it all

together and machine it all to make it one seamless um, housing. This isn't

um, housing. This isn't um super cheap, but it's less expensive than say for example an oil cooling.

You'd have to buy an oil pump and an oil to water heat exchanger uh as separate components and then the integration

problem of tuning your oil flow and your pump flow for the operating conditions of the vehicle. Um so different companies are using different solutions

for this. uh for the China market, this

for this. uh for the China market, this is a really great solution. Uh and I'm happy to see it in in the in this drive

unit from BYD.

Uh I'm not sure I would recommend this for uh Western Europe or the US market.

Um all right. In the for the drive unit, the uh the gearbox, um we have really a pretty standard gearbox. It's a two-stage gearbox. The

gearbox. It's a two-stage gearbox. The

This is an input shaft that the motor rotor uh drives this and then this is the lay shaft, a secondary shaft uh that produces some of the gear half the gear

reduction and then this other half the gear reduction is t done by the differential um and then the two shafts going half shafts going out to the

wheels um go out here. Um this is a fantastic example and has very low friction. I would normally spin it, but

friction. I would normally spin it, but I don't have this bearing seated because this this bearing was a press fit, and I don't want to have to pull it back out again because it was tough to pull out.

Um, one thing that stands out though on this is how compact this whole unit is.

They've arranged the the three gears as as tightly as possible for this gear reduction. Um, and for the loads that

reduction. Um, and for the loads that this has to handle, it's a pretty high torque motor. Um, and it's a high-speed

torque motor. Um, and it's a high-speed motor, so very compact, uh, gear reduction. Um, and,

reduction. Um, and, uh, this casting, uh, form fit right around. Um, what that

helps with is the oil flow. So the the differential outside gear picks up the oil and slings it up into pockets at the

top and then the oil uh drains down through channels in the casting uh to lubricate all the bearings. So no uh

dedicated oil pump for um lubrication on the um gears. It's all done by slinging oil um the action by the action of the

gears. Um very cost-e effective solution

gears. Um very cost-e effective solution for um keeping everything lubricated.

They don't need this to run this oil all over the motor um for cooling. It's only

um contained here in the gearbox.

So that's the the gearbox. Uh excellent

example again.

Taken as a whole uh and stepping back and costing out each of these items, we see that this uh

motor and drive unit is very likely the lowest cost drive unit that we have ever encountered for this capability uh over

200 horsepower type um drive unit. And

so even at the low cost that uh we have for this for the China market right now and the competitive pressure that BYD is

under, it's almost certainly still not enough. So, I know that BYD is coming

enough. So, I know that BYD is coming back to Borg Warner and looking for even more cost-saving ideas, even though this

sets a new benchmark for finding ways to reduce cost in every single component as we go. All right, I'm going to come back

we go. All right, I'm going to come back to the stator in a little bit. Um, it's

an interesting stater um although it's a kind of a standard winding diagram, but uh we're we'll talk about it in a

little bit. I'm going to jump to the

little bit. I'm going to jump to the rotor here. Um the rotor is a interior

rotor here. Um the rotor is a interior magnet PM machine has uh a double V construction for the the magnets. And

we're going to do a another video another time to talk about exactly why uh these motor manufacturers are going with interior permanent magnets that

always seem to have either a single V or a double V construction and what they what the benefit of that is. But uh it's

it's been this this construction for uh permanent magnet motor has become ubiquitous in the in the industry. Um,

we see Hyundai using it. We see GM using it. Ford is using it. Um, Toyota

it. Ford is using it. Um, Toyota

practically originated it back in the day with the Prius. Um, uh, Nissan is using it. Uh, just goes the list goes on

using it. Uh, just goes the list goes on and on. Uh, just about every major

and on. Uh, just about every major manufacturer is using a a variation on this type of rotor. But nobody is

putting a deep groove in the OD outside diameter like this. Norm, this is a very high-speed rotor and it spins at almost

20,000 RPM and normally you want to have an unbroken uh outside diameter because you want the

hoop stress for the um steel laminations to be uniformly distributed around the the perimeter.

So this groove that required some detailed engineering and finite element analysis in order to design the radi on

this the radiuses and design the depth of that groove in order to make it structurally hold together when this thing is spinning at extremely high speed. One thing that does help them is

speed. One thing that does help them is that the diameter of this rotor is a little bit smaller than the diameter that we see other companies use. The

typical diameter is 150 millimeters or about 6 in. And this is more like 138 millimeters, just a little bit smaller to reduce the

stress on the outside diameter and allow them to do this. What they get from that normally with this double V construction of the magnets, it focuses the magnetic

field into the center and it produces a a a prominent spike of uh magnetic flux coming out of the

center of the of the rotor. By putting

in this groove, it flattens out that um prominent spike of flux and makes the flux from the magnets uh much more sinosoidal

and that helps reduce loss in the motor.

Um so it's addition it it reduces torque ripple and noise but it also reduces loss um by smoothing out the flux from

the rotor. So that's very interesting

the rotor. So that's very interesting and I haven't seen that in other rotors before the permanent magnet rotors and

it's interesting um adaptation.

Okay, let's take talk about this inverter. Uh very thin inverter

inverter. Uh very thin inverter uh pancake, you know, like a pizza box type style that sits nice and flat on top of the motor. This is a rear motor

application and so it's very important.

And I'm sure BYD had tight regular specifications for the maximum height of this inverter uh because they need to give the customer in the you know the

trunk space um as much as possible. You

don't want to encroach on the uh passenger compartment and so there's a very little space between you know the bottom of the of the drive unit and the

ground and the top of this drive unit.

So, keeping this as as thin as possible was a key part of the design that caused it to spread out a little bit. Um, it

has all the usual components. The DC

energy comes in from the battery here, goes into a large capacitor. This helps

smooth out the the current ripple that comes from the motor and stores energy for the switching events so that it can

fill in the gaps of the of the switching events. So that's what the capacitor is

events. So that's what the capacitor is there for. These are the switches. There

there for. These are the switches. There

are six switches in here. Uh actually

it's 12 is two is pairs. They're are

discrete devices.

Um, and I haven't seen this kind of packaging before. Um, it's cooled on

packaging before. Um, it's cooled on both sides. We have this uh cooling

both sides. We have this uh cooling channel on the top and cooling channel on the bottom. Other companies do this

sim something similar uh but not this thin. The the switching devices are only

thin. The the switching devices are only four millimeters thick. Uh so they must be going like bare dye um right onto the

substrate and then directly connected to the cooling. Uh it's uh you want to have

the cooling. Uh it's uh you want to have as as thin uh and and low resistance cooling path as possible with these

switches to be able to handle the thermal um load.

And so these guys, this is a step above what I've seen done in in other um inverters in the industry.

Uh very um novel I think uh for how this is done. Also the fact that they're using

done. Also the fact that they're using this copper, it's of course a great thermal conductor, but it also is electrical conductor. And this provides

electrical conductor. And this provides shielding by putting copper on both the top and the bottom of the switching devices. The electromagnetic

devices. The electromagnetic interference that is generated by these switching devices is shielded from all the rest of the components. On the back

side, we've got these uh these are the gate drive controllers,

and these can be relatively sensitive to um electromagnetic interference. And so

having the the shielding on both sides of the switching devices helps shield that uh sensitive electronics from from

the noise of this. There's actually the amazing thing is there is um as much power going through these switches as

there is in a whole neighborhood uh of homes. So 15 or 20 homes could be lit up with the power that's going

through this uh these switches at at when you're doing full max pedal acceleration.

And so shielding the um all the components from that power is essential especially these three devices here. These are the current

devices here. These are the current sensors and they do not have a uh usually there's a steel yolk around

each of the current sensors to sort of contain the magnetic field of the three phases. And

if we look underneath the three-phase current coming from the switches uh and going down to the motor passes directly underneath

these three um current sensors.

So it picks up the the current without uh shielding without the magnetic uh steel around it. Um which is a huge cost

save and uh package savings. is much

more compact. Um, normally these things are quite uh large and heavy. Uh, and

that's only really made possible by this uh fully shielded switching package. So,

great little tight compact package that enables some cost savings as well. Um,

win-win situation. The other thing I love to point out is um this is all one casting.

Uh then and the controller is mounted on the other side and this controller is again shielded from the electromagnetic interference

not just by the cooling channels but by the casting itself by mounting it on the opposite side using this single casting.

Other companies use a separate cast um part as the shield to shield the essentially the controller from that.

And here they've done that with a single part. And they they don't uh put a big

part. And they they don't uh put a big another heavy casting over the top of it. They use a stamping

it. They use a stamping um aluminum stamping to cover it. So the

this whole cover is just an a lowcost stamping. Companies will say, "Oh, we

stamping. Companies will say, "Oh, we can't use a stamping um because we have to mount the cover over here." But these

they have these nice inserts to drive the screws into. I will have to give them uh a little bit of grief.

Freund screws to put this. I don't know what it is about electrical engineers and their love of little bitty screws and hundreds of them. Um, there are

better ways to put things together. It's

yes, screws are tried and true, but uh it's there's there's other ways to do this.

And this represents a lot of process time. And every one of these screws is a

time. And every one of these screws is a potential failure mode. when screws tend to back out under vibration and thermal

cycling and then you've got, you know, if one of these screws that's holding in these switches and making this electrical connection, if it backs out,

you've got arcing and you got a failed inverter. So, not thrilled with uh using

inverter. So, not thrilled with uh using a million screws. But that's that's a part of the the current state of

electrical engineers doing mechanical design work. Um, okay.

design work. Um, okay.

Absolutely love almost everything about this motor, but it wouldn't be a Monroe Live video if we didn't find something that we're really not fond of. Yeah, of

course we always pick on the screws, but there's more to it. And so I'm going to go back to the stator.

I have a there's a fond place in my heart for this particular electromagnetic design. It's a 72 slot

electromagnetic design. It's a 72 slot design. This one's a six pole motor. Has

design. This one's a six pole motor. Has

three parallel paths. Uh back in the day we did the Chevy Bolt. It was also a 72 slot design. Three parallel paths. Eight

slot design. Three parallel paths. Eight

pole motor. Um, in fact, they have an eight-pole version of this stator um in the BYYD Shark. So, they're uh doing six

pole and eight pole versions of this same uh or nearly the same

uh uh layout. This motor is a part of a family of motors that get power all the way from

uh 350 kilowatts or more uh down to under under about 150 kilowatts or perhaps even less. I haven't seen the

whole range. Um so it's a very flexible

whole range. Um so it's a very flexible winding pattern. Um and I love the uh

winding pattern. Um and I love the uh bar winding scheme. They've uh they've minimized the number of special

uh um conductors here and produc done a a a great job with uh running the the three parallel paths and

balancing the the electromagnetic um winding so that you have the same inductance in all three parallel paths.

So that's all very good. they've made

one uh one there's one thing that they where they've broken a cardinal rule and yeah sometimes you have to break the rules to

get the kinds of cost savings that you're looking for. Um I'm this in this case I think that it's not going to be not going to work out well for them.

These connections here they're using these flex leads here. There's a

stranded wound uh stranded cable where the ends are welded onto these two terminals.

That allows them the tolerance stack up because this ends up uh moving somewhat and there's you can't be guaranteed

between the location of this and the location of the inverter connections.

um that everything will be exactly where it's supposed to be. And so a little flexibility is great. Helps for um for manufacturing and and assembly,

but you have to support both ends. This end

is supported at the inverter in a plastic block that holds everything tight, but this end

is free to move. Um, it's only supported by the wires from the stator. And it's

this weld here, the same welds that we're using to conduct the electricity into the winding. And the cardinal rule,

the general engineering rule of thumb is you do not want your electrical connection to be the same thing that carries the

mechanical support. So you want to have

mechanical support. So you want to have the mechanical support carried by a mechanical part and the electrical connection

being free from mechanical stress. So

what we're what happens here is when we run current through this, we run hundreds of amps through this. This

heats up and this heats up. So and when it heats up, the copper expands and when the copper expands, it pushes down on this and then this also the copper

expands. And so these three push up. So

expands. And so these three push up. So

this is up and this is down and it flexes that joint. and then you turn it off and it cools back off and it flexes the other way. And so over time it

flexes back and forth every time you turn the motor on and off. In addition

to that, just the weight of this as you vibrate this, as you go over the road and every bump in the road, you get a little vibration and that's also putting

stress on that joint. And then there's further vibration. The action of the

further vibration. The action of the rotor spinning around is moving these wires. The magnetic fields are so strong

wires. The magnetic fields are so strong that it actually distorts this housing and and produces a high frequency

vibration that again moves this joint.

So between all of those forces, this joint ends up seeing quite a lot of vibration. And unfortunately,

vibration. And unfortunately, copper, the kind of copper you want for great conductivity to produce low loss motors,

is not a very good material for structural support. And over time,

structural support. And over time, fatigue sets in and little cracks will turn into big cracks and this will saw

itself right in half.

So, that's that's an issue. it. Uh I'm

sure that they did the FEA and they've done some testing to make sure that uh it meets the requirements.

The only trouble is that these weld joints are notoriously um variable.

All it takes is someone to not uh to go a little bit long on the maintenance schedule of the welder and suddenly you've got a joint that's not quite the

same as the joint that they tested. And

now you've got one that isn't going to last as well as the one you tested and you end up with problems in the field

and it it's trouble. The way to fix that is you can put a plastic part underneath this, just a little bit of support underneath this to dampen those

vibrations.

Uh, and then that completely eliminates the issue. So, the mechanical load is

the issue. So, the mechanical load is handled by the the little plastic part and supported. No one likes adding an

and supported. No one likes adding an extra part. And at Monroe, we always

extra part. And at Monroe, we always advise to eliminate any part that's unnecessary.

But don't go too far. And if you need to have a part to perform a function, which means in this case providing the

mechanical support to protect that electrical joint, then you need to add the part. And so, you know, a plastic

the part. And so, you know, a plastic part kind of like they did up here with this this side, another plastic part down here to support on on on this side

of the joint would be beneficial. So

absolutely love this motor. Uh

and I think that this is a new benchmark for compact cost effective uh electrical

power for EVs and hybrid vehicles. Uh

there's going to be technology taken from this motor and applied across the industry. Uh BYD is to be commended for

industry. Uh BYD is to be commended for setting a new benchmark and Borg Warner along with them and getting this new technology on the road and it'll be

really fun to see how how this technology propagates out into other manufacturers designs. So thanks for

manufacturers designs. So thanks for watching here at Monroe Live and we'll see you next time.