By Atul Gopal
Atul Gopal from PluginIndia and some members of the Nexon EV owners community were invited to Tata Motor's electric car factory. Here are his notes from the visit.
Reached TML Training Division Hostel at 0830 hrs. This houses the EV subsidiary of TML now. (Wonder where the Full Time Apprentices of TML are staying now!) Chandrakant ji (head of RnD) was there when I reached – he introduced me to Umesh, who looks after vehicle integration. Gave him some feedback based on experience with the Mumbai-Himachal Tigor EV trip.
Around 0900 hrs, the Nexon owners gang landed up. Was nice to catch up with Ashish, Vivek and the Delhi Nexon gang. Also met with Arun, who had flown in from Bangalore. There was an interesting duo from Kerala – one of them could only speak Malayalam. He runs a Malayalam EV YT channel. There were about 28 of us. After a quick breakfast, Anand Kulkarni briefed us about the Nexon story. He had been a speaker at a PII event in March – and though most of the talk was similar to what he had delivered then, there were a few changes. The good news is that TML has a 93% market share in the EV space. I expect that to come down once the likes of Ola enter the market. There is also some hope from Mahindra’s re-entry. But Tata is doing more than a wait and watch – we have been promised 10 more EVs by 2025. I hope there is at least one which is a grounds up design.
Anand shared a demographic profile of Nexon EV buyers. 2/3rd are salaried folks – and 1/3rd are either entrepreneurs or self employed. Was surprised to see this 1/3rd figure. In a general population, I would have expected a lesser density of the entrepreneurs. Was nice to watch video clips of the Nexon battery pack being put in a petrol fire, dumped into a water tank etc. The battery connectors are specially designed for IP67 batteries – and are designed to prevent water ingress short circuits.
After Anand’s talk, we were broken into 4 groups – and assigned a TML executive who would take us around the facilities, round robin style – so that there was no overcrowding. Our group started with the test track, where we witnessed a water wading test. The Nexon EV was going through 300 mm of water – sans any problems. Then there was the gradeability test. Got to understand the difference between degrees and percent at the track. The steepest gradient on the track, used to test military vehicles, is 26 degree, which translates to 50%. The math is that tan 26 = 0.5. The gradient that the Nexon EV has been tested on is 0.18 or 10 degree.
We then went on to a test track drive of the Nexon EV Max. Two things to note – max speed of Nexon has been upped to 140 kmph. And Electronic stability has been added. The motor remains the same as the regular Nexon, but has been electronically allowed to draw more amps. The battery pack has been modified. There is a hump at one end of the pack to accommodate the extra cells. That hump fits nicely below the passenger seats. We reached 140 kmph on the 1.2 km track –and also experienced lane changes at 120 kmph. No doubt, the Nexon Max has seen improvements in the already great handling.
We then went on to the ERC test labs. What was most interesting was the crash test facility. It’s basically a 100 m puller which accelerates the vehicle to whatever speed is desired in the test. For the Nexon crash test speeds range from 29 to 50 kmph. In the last 10 m of travel the puller is detached from the vehicle. There are a lot of high speed cameras at the end of the track, where the crash barriers are placed. The action in an accident happens in 100 ms. The high speed cameras are required to playback this action in slow motion. These cameras typically shoot 1000 frames a second. The government has stipulated norms for the types of crash tests that a vehicle needs to go through for NCAP ratings. The crash test facility was put up in 2004 – and off late, TML is taking the crash business very seriously – making safer cars – that have started denting Suzuki’s relatively light and fuel efficient cars.
We were assured that crash tests have been done for the Nexon EV too. We did see a dented Nexon EV in the facility. But I have yet to see separate NCAP ratings released by TML in their publicity material for EVs – so I have my doubts about how many of these tests have been performed for the EV specifically. One interesting discussion happened on the crash test dummies. Each of the dummies costs almost a crore – and are full of accelerometers which measure deceleration rates in a crash. Btw, there are accelerometers installed in the cab as well – the favourite place being the B pillar to see how the cabin is slowing down in the crash. The human body can only sustain a certain amount of g forces before damage starts. In a high speed crash, the rib cage can get blocked by the airbag – but the internal organs in the abdominal cavity continue to move forward – and dash against the rib cage, leading to rupture and internal bleeding. So the trick is to slow down the g rates – by allowing parts of the vehicle to deform and absorb the energy of the crash.
There are crash test dummies for different percentiles of the population – alas all the percentile ranking is based on US populations. India does not make any crash test dummies of its own. One inhibiting factor is that we are not allowed to do cadaver studies in the tests, which are an important input in dummy development. It would be a good idea for the crash test folks to visit accident sites and actually check out what is happening with their vehicles in real life crashes. This is where theory would meet practice.
We then moved on to the other labs – two of them were for simulating road tests. Road data is collected and fed into the equipment, which then simulates each bump on the road by pushing the
respective wheel through a hydraulic cylinder. The smooth road data is deleted, so that the test can be run at 3X speed. Most of this work is to help fine tune the suspension. The suspension is an interesting amalgamation of metal and rubber – so its behaviour tends to be non-linear, and therefore challenging to model. Which is why labs like these are required. During the test, the toe, camber and caster changes in the vehicle are measured, as stuff like cornering is simulated. We asked the lab-in-charge of any changes that have been made based on this testing. For the Nexon EV specifically, the rear twist beam was fitted with a stiffer spring – as the rear wheel loads had increased. This equipment also end up testing fasteners and weld quality.
We then drove on to the environmental chambers – where you can fit an entire truck inside. There were two chambers in operation – one was seeing an Altroz being tested in an ambient of 45 C – 30% humidity. There is a front wheel dynamometer so that data is gathered with the engine running and the gearbox engaged. There is a blower at the front of the vehicle which throws air based on vehicle speed. Light at 1200 W per sq m is put on the vehicle. You can also tilt some of the light fixtures to simulate the pre-noon sun. We then peeked into the anechoic (no echo) NVH chamber. There are wedges filled with glasswool to absorb the sound. The chamber’s floor is on rubber mounts so that vibrations from the surrounding roads and buildings are not passed on to the chamber. There is also a one meter gap between inner and outer walls to remove air noise. In such a silent situation, it is easy to identify the source of noise. The chamber has again got a chassis dynamometer with simulated tar and concrete surfaces.
We then went on the weld line for the cab. We were shown the Altroz line. Quite a bit of automation has happened – though material handling is still done by humans. They can surely invest in Ola factory style automated Lidar vehicles. The weld line has been supplied by Kuka. Was fun to watch the arms going about the welding operations. Like in stitching, the welding is done in two stages – coarse and fine. First there are fewer spot welds done to get the body frame in place. In the last few stations – more spot welds are done to strengthen the shell. This is called respotting. One of the machines was interesting – it was a 4000 kW laser brazing machine (am not too sure if I got the power consumption right). The roof is a critical area for leakage. So the joining of the side and the roof panels is done by a laser heated brazing. Also, I saw a lot of copper studs attached to the inside of the cab. These are where the different electrical equipment are earthed.
We were to also have a dekko at the truck line – but we decided to skip that as we were running late. So ended with the EV assembly line. The welded Nexon cab is sent over to the Fiat JV plant in Ranjangaon. It is painted there – and also cab and suspension fitments happen there. The tyres are put on – and this unit – which TML internally calls a glider – is sent back to a small facility in K block where the battery pack and drive train is added. During the initial days, the company did not expect too much from the EV project – so it set up a garage assembly operation for making 10 units a day. The same setup is now able to achieve a throughput of 80. Just for comparison, TML is churning out about 550 per day of the Petrol and Diesel Nexons. At the K block operation, the Nexon Max EVs are being assembled. The Ranjangaon plant, in the meantime, has started assembling the regular Nexon EVs. They are doing about a hundred a day. Should check with Ravi Gogia whether they have a similar garage setup – or are using an assembly line for the same. The Tigor EV, incidentally, is assembled at the Sanand plant. TML has purchased the Ford factory in Sanand – and hopefully will be having an exclusive EV factory there. The rumour is that the first car to roll out from there will be the Tiago EV. Sensible decision – Tata needs to make more small cars and fewer SUVs to help in India’s drive towards sustainable mobility.
The Max has seen a modification in the electronics packaging. The onboard charger, the power distribution unit and the DC/DC converter have all been got into a single unit. All of these were earlier separate aggregates, supplied by Shanghai Motor. (The same guys who make MG.) Now the single unit is made in India by a JV between Valeo and Siemens. This repackaging, I am sure, would lead to an increase in reliability – as three connectors would get eliminated. In addition to this combined unit, the drive train has the motor, the gearbox (differential) and the inverter. The indigenization of the inverter has also happened. Next in line is the gearbox. The onboard charger can take up to 7 kW of charging – incidentally through single phase AC. The current is now up to 25 A from the earlier 15 A. Will require a special socket at the user end. Existing Nexon owners unfortunately cannot upgrade to this charger because of its presence in the combo pack.
The weight of the max battery pack has gone up by 52 kg, which is not too bad for a 33% increase in battery size. The earlier 30 kWh pack weighs 280 kg. There has been a 33% increase in size, so I would have expected a 90 kg increase, but then the safety and packaging weights don’t go up in the same proportion as battery capacity. Cells used are FF32155, 15 Ah prismatic. Voltage is 332.8 V. The motor to drive the AC and battery cooling circuit probably draws between 1 to 2 kW of energy. There is a compact heat exchanger where the refrigerant cools down the water based glycol coolant. This circulates through the cooling paths inside the battery pack. One more kaizen that is going to be coming soon is encapsulating the HV cables which go through the vehicle under-body in trays. This will prevent damage from mickey mouse and friends.
We were driven back in the open Tata Wingers to the training hostel after this. The security has now been handed over to a contractor; in the nineties the security folks were all employees of the company – with the head of the security reporting directly to the Executive director. After a sumptuous lunch at the hostel, there was a feedback session. Ashish ji, Vivek ji – and one gentleman from the Pune group were most vocal. Quite a few constructive ideas were discussed to improve the service experience. The 1800 number given on the vehicles is hardly picked up. Typically takes 20 minutes before it gets answered. RSA’s take their own sweet time to respond. And this is one of the main reasons for a deluge of tweets and social media posts. TML can definitely be proactive on this front. Another suggestion was that the vehicle error logs should be shared with users through the Tata app. Maybe it will help in problem diagnosis better – and at times even eliminate a visit by RSA or towing to the dealership. Tata is mulling over the idea of having exclusive EV service centers – and would be much appreciated if that happens. Some users reported a consistent plug overheating and auxiliary battery drain. It was around 1500 hrs by the time we ended.
Caught up with Randeep Khokar, who looks after Electricals and Electronics at ERC – and Raghupati Karanth – who is a veteran at PE, the department that makes the sheet metal dies for vehicles.
Had a long chat with Jaydeep Desai too. He was earlier head of manufacturing at K block – and am happy to report that under him TML upped car production from a hundred to a thousand a day. Jaydeep has also been part of the Nano team and has spent 3 years at Singur. Was interesting to hear stories from those times – and hear about Nandigram, and the intersection of politics and economics. Singur is still a place in ruins. When you have dug foundations tens of meters into the substrata – then you don’t really expect the farms to spring back to life. But there is still a lot of symbolism in Singur. Singur gave people the belief that there is an angry young woman who could challenge the hegemony of the old Marxists. At the height of the violence, Ratan Tata called the team over to Taj Bengal and apologised to each of them. He took on personal responsibility for the mess – and informed the team that the project is shifting away from Singur. Within a few weeks, the team was packing its bags for Sanand. Sanand was an interesting contrast to Singur. The then CM, and current PM, actually got the DM of Ahmedabad to become the single window for the Sanand factory – and set a deadline of 1 year for the project to get completed. Jaydeep was surprised by the initiative shown by the collector – and thanks to immense help from government agencies, the project did come up in a year’s time.
All three of the above folks joined TML in June 1990, the same year that I joined . We will be meeting at my place for dinner on July 03. A belated bachelor’s party. Graduate Engineer Trainees of the 1990 batch are welcome to join.
Around 0900 hrs, the Nexon owners gang landed up. Was nice to catch up with Ashish, Vivek and the Delhi Nexon gang. Also met with Arun, who had flown in from Bangalore. There was an interesting duo from Kerala – one of them could only speak Malayalam. He runs a Malayalam EV YT channel. There were about 28 of us. After a quick breakfast, Anand Kulkarni briefed us about the Nexon story. He had been a speaker at a PII event in March – and though most of the talk was similar to what he had delivered then, there were a few changes. The good news is that TML has a 93% market share in the EV space. I expect that to come down once the likes of Ola enter the market. There is also some hope from Mahindra’s re-entry. But Tata is doing more than a wait and watch – we have been promised 10 more EVs by 2025. I hope there is at least one which is a grounds up design.
Anand shared a demographic profile of Nexon EV buyers. 2/3rd are salaried folks – and 1/3rd are either entrepreneurs or self employed. Was surprised to see this 1/3rd figure. In a general population, I would have expected a lesser density of the entrepreneurs. Was nice to watch video clips of the Nexon battery pack being put in a petrol fire, dumped into a water tank etc. The battery connectors are specially designed for IP67 batteries – and are designed to prevent water ingress short circuits.
After Anand’s talk, we were broken into 4 groups – and assigned a TML executive who would take us around the facilities, round robin style – so that there was no overcrowding. Our group started with the test track, where we witnessed a water wading test. The Nexon EV was going through 300 mm of water – sans any problems. Then there was the gradeability test. Got to understand the difference between degrees and percent at the track. The steepest gradient on the track, used to test military vehicles, is 26 degree, which translates to 50%. The math is that tan 26 = 0.5. The gradient that the Nexon EV has been tested on is 0.18 or 10 degree.
We then went on to a test track drive of the Nexon EV Max. Two things to note – max speed of Nexon has been upped to 140 kmph. And Electronic stability has been added. The motor remains the same as the regular Nexon, but has been electronically allowed to draw more amps. The battery pack has been modified. There is a hump at one end of the pack to accommodate the extra cells. That hump fits nicely below the passenger seats. We reached 140 kmph on the 1.2 km track –and also experienced lane changes at 120 kmph. No doubt, the Nexon Max has seen improvements in the already great handling.
We then went on to the ERC test labs. What was most interesting was the crash test facility. It’s basically a 100 m puller which accelerates the vehicle to whatever speed is desired in the test. For the Nexon crash test speeds range from 29 to 50 kmph. In the last 10 m of travel the puller is detached from the vehicle. There are a lot of high speed cameras at the end of the track, where the crash barriers are placed. The action in an accident happens in 100 ms. The high speed cameras are required to playback this action in slow motion. These cameras typically shoot 1000 frames a second. The government has stipulated norms for the types of crash tests that a vehicle needs to go through for NCAP ratings. The crash test facility was put up in 2004 – and off late, TML is taking the crash business very seriously – making safer cars – that have started denting Suzuki’s relatively light and fuel efficient cars.
We were assured that crash tests have been done for the Nexon EV too. We did see a dented Nexon EV in the facility. But I have yet to see separate NCAP ratings released by TML in their publicity material for EVs – so I have my doubts about how many of these tests have been performed for the EV specifically. One interesting discussion happened on the crash test dummies. Each of the dummies costs almost a crore – and are full of accelerometers which measure deceleration rates in a crash. Btw, there are accelerometers installed in the cab as well – the favourite place being the B pillar to see how the cabin is slowing down in the crash. The human body can only sustain a certain amount of g forces before damage starts. In a high speed crash, the rib cage can get blocked by the airbag – but the internal organs in the abdominal cavity continue to move forward – and dash against the rib cage, leading to rupture and internal bleeding. So the trick is to slow down the g rates – by allowing parts of the vehicle to deform and absorb the energy of the crash.
There are crash test dummies for different percentiles of the population – alas all the percentile ranking is based on US populations. India does not make any crash test dummies of its own. One inhibiting factor is that we are not allowed to do cadaver studies in the tests, which are an important input in dummy development. It would be a good idea for the crash test folks to visit accident sites and actually check out what is happening with their vehicles in real life crashes. This is where theory would meet practice.
We then moved on to the other labs – two of them were for simulating road tests. Road data is collected and fed into the equipment, which then simulates each bump on the road by pushing the
respective wheel through a hydraulic cylinder. The smooth road data is deleted, so that the test can be run at 3X speed. Most of this work is to help fine tune the suspension. The suspension is an interesting amalgamation of metal and rubber – so its behaviour tends to be non-linear, and therefore challenging to model. Which is why labs like these are required. During the test, the toe, camber and caster changes in the vehicle are measured, as stuff like cornering is simulated. We asked the lab-in-charge of any changes that have been made based on this testing. For the Nexon EV specifically, the rear twist beam was fitted with a stiffer spring – as the rear wheel loads had increased. This equipment also end up testing fasteners and weld quality.
We then drove on to the environmental chambers – where you can fit an entire truck inside. There were two chambers in operation – one was seeing an Altroz being tested in an ambient of 45 C – 30% humidity. There is a front wheel dynamometer so that data is gathered with the engine running and the gearbox engaged. There is a blower at the front of the vehicle which throws air based on vehicle speed. Light at 1200 W per sq m is put on the vehicle. You can also tilt some of the light fixtures to simulate the pre-noon sun. We then peeked into the anechoic (no echo) NVH chamber. There are wedges filled with glasswool to absorb the sound. The chamber’s floor is on rubber mounts so that vibrations from the surrounding roads and buildings are not passed on to the chamber. There is also a one meter gap between inner and outer walls to remove air noise. In such a silent situation, it is easy to identify the source of noise. The chamber has again got a chassis dynamometer with simulated tar and concrete surfaces.
We then went on the weld line for the cab. We were shown the Altroz line. Quite a bit of automation has happened – though material handling is still done by humans. They can surely invest in Ola factory style automated Lidar vehicles. The weld line has been supplied by Kuka. Was fun to watch the arms going about the welding operations. Like in stitching, the welding is done in two stages – coarse and fine. First there are fewer spot welds done to get the body frame in place. In the last few stations – more spot welds are done to strengthen the shell. This is called respotting. One of the machines was interesting – it was a 4000 kW laser brazing machine (am not too sure if I got the power consumption right). The roof is a critical area for leakage. So the joining of the side and the roof panels is done by a laser heated brazing. Also, I saw a lot of copper studs attached to the inside of the cab. These are where the different electrical equipment are earthed.
We were to also have a dekko at the truck line – but we decided to skip that as we were running late. So ended with the EV assembly line. The welded Nexon cab is sent over to the Fiat JV plant in Ranjangaon. It is painted there – and also cab and suspension fitments happen there. The tyres are put on – and this unit – which TML internally calls a glider – is sent back to a small facility in K block where the battery pack and drive train is added. During the initial days, the company did not expect too much from the EV project – so it set up a garage assembly operation for making 10 units a day. The same setup is now able to achieve a throughput of 80. Just for comparison, TML is churning out about 550 per day of the Petrol and Diesel Nexons. At the K block operation, the Nexon Max EVs are being assembled. The Ranjangaon plant, in the meantime, has started assembling the regular Nexon EVs. They are doing about a hundred a day. Should check with Ravi Gogia whether they have a similar garage setup – or are using an assembly line for the same. The Tigor EV, incidentally, is assembled at the Sanand plant. TML has purchased the Ford factory in Sanand – and hopefully will be having an exclusive EV factory there. The rumour is that the first car to roll out from there will be the Tiago EV. Sensible decision – Tata needs to make more small cars and fewer SUVs to help in India’s drive towards sustainable mobility.
The Max has seen a modification in the electronics packaging. The onboard charger, the power distribution unit and the DC/DC converter have all been got into a single unit. All of these were earlier separate aggregates, supplied by Shanghai Motor. (The same guys who make MG.) Now the single unit is made in India by a JV between Valeo and Siemens. This repackaging, I am sure, would lead to an increase in reliability – as three connectors would get eliminated. In addition to this combined unit, the drive train has the motor, the gearbox (differential) and the inverter. The indigenization of the inverter has also happened. Next in line is the gearbox. The onboard charger can take up to 7 kW of charging – incidentally through single phase AC. The current is now up to 25 A from the earlier 15 A. Will require a special socket at the user end. Existing Nexon owners unfortunately cannot upgrade to this charger because of its presence in the combo pack.
The weight of the max battery pack has gone up by 52 kg, which is not too bad for a 33% increase in battery size. The earlier 30 kWh pack weighs 280 kg. There has been a 33% increase in size, so I would have expected a 90 kg increase, but then the safety and packaging weights don’t go up in the same proportion as battery capacity. Cells used are FF32155, 15 Ah prismatic. Voltage is 332.8 V. The motor to drive the AC and battery cooling circuit probably draws between 1 to 2 kW of energy. There is a compact heat exchanger where the refrigerant cools down the water based glycol coolant. This circulates through the cooling paths inside the battery pack. One more kaizen that is going to be coming soon is encapsulating the HV cables which go through the vehicle under-body in trays. This will prevent damage from mickey mouse and friends.
We were driven back in the open Tata Wingers to the training hostel after this. The security has now been handed over to a contractor; in the nineties the security folks were all employees of the company – with the head of the security reporting directly to the Executive director. After a sumptuous lunch at the hostel, there was a feedback session. Ashish ji, Vivek ji – and one gentleman from the Pune group were most vocal. Quite a few constructive ideas were discussed to improve the service experience. The 1800 number given on the vehicles is hardly picked up. Typically takes 20 minutes before it gets answered. RSA’s take their own sweet time to respond. And this is one of the main reasons for a deluge of tweets and social media posts. TML can definitely be proactive on this front. Another suggestion was that the vehicle error logs should be shared with users through the Tata app. Maybe it will help in problem diagnosis better – and at times even eliminate a visit by RSA or towing to the dealership. Tata is mulling over the idea of having exclusive EV service centers – and would be much appreciated if that happens. Some users reported a consistent plug overheating and auxiliary battery drain. It was around 1500 hrs by the time we ended.
Caught up with Randeep Khokar, who looks after Electricals and Electronics at ERC – and Raghupati Karanth – who is a veteran at PE, the department that makes the sheet metal dies for vehicles.
Had a long chat with Jaydeep Desai too. He was earlier head of manufacturing at K block – and am happy to report that under him TML upped car production from a hundred to a thousand a day. Jaydeep has also been part of the Nano team and has spent 3 years at Singur. Was interesting to hear stories from those times – and hear about Nandigram, and the intersection of politics and economics. Singur is still a place in ruins. When you have dug foundations tens of meters into the substrata – then you don’t really expect the farms to spring back to life. But there is still a lot of symbolism in Singur. Singur gave people the belief that there is an angry young woman who could challenge the hegemony of the old Marxists. At the height of the violence, Ratan Tata called the team over to Taj Bengal and apologised to each of them. He took on personal responsibility for the mess – and informed the team that the project is shifting away from Singur. Within a few weeks, the team was packing its bags for Sanand. Sanand was an interesting contrast to Singur. The then CM, and current PM, actually got the DM of Ahmedabad to become the single window for the Sanand factory – and set a deadline of 1 year for the project to get completed. Jaydeep was surprised by the initiative shown by the collector – and thanks to immense help from government agencies, the project did come up in a year’s time.
All three of the above folks joined TML in June 1990, the same year that I joined . We will be meeting at my place for dinner on July 03. A belated bachelor’s party. Graduate Engineer Trainees of the 1990 batch are welcome to join.
Tata Motors Owner Community Members at Tata campus
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