LG Innotek has developed a Wireless Battery Management System (Wireless BMS) that improves battery performance. A BMS is an essential control system that monitors the voltage, current, temperature, etc. of a battery to optimize its performance and life span.
The wireless BMS that LG Innotek developed is embedded with an Radio Frequency (RF) communication module that combines essential components for wireless communication, such as a RF communication chip and antenna, into one unit for the first time. The key advantage of a wireless BMS is that it contributes to reducing the weight of vehicles mounted with a BMS.
Once the cables connected to the BMS are removed, the vehicle weight is reduced by 66~198Ib. Removing the dozens of cables and connectors required for a BMS reduces both the weight and volume of a battery pack.
This secures additional space of 10~15% for a battery pack, enabling increasing the capacity of a battery, and hence, the range of an EV. It has been confirmed that a wireless BMS increases the mileage of an electric vehicle by up to 12 miles. The additional space for a battery pack also improves the flexibility of battery design .
In addition, the possibility of a cable or connector failure due to vehicle vibration is completely removed. Furthermore, battery pack assembly previously done manually due to the complexity of cable connections can now be automated using a robot, achieving cost reduction.
LG Innotek had already developed an 800V wired BMS in 2020. Since the charging duration decreases as the voltage increases, domestic and overseas automobile makers tend to adopt 800V as their voltage system for electric vehicles.
To send and receive data for an electric vehicle battery wirelessly, a wireless BMS must be equipped with dozens of components such as an RF circuit, RF communication chip and antenna.
In the case of previously released wireless BMS, these components were attached one by one to a PCB. Because of this, the BMS production process required a lot of time and there was too much development burden in expanding the product lineup, LG Innotek said.
LG Innotek instead first applied to its wireless item an RF communication module that it had developed using its high-precision, high-density, multi-layer board technology. The RF communication module is composed of a four-layer board and dozens of wireless communication components that were densely integrated into this board. This structure helped the company to develop a wireless BMS on which the battery pack could be mounted much more easily.
The RF communication module mounted on the company’s wireless BMS is designed to be compatible with all types of communication chips. This compatibility enables applying the company’s Wireless BMS easily to all electric vehicles produced by its clients.
LG Innotek plans to start mass production of the wireless BMS in 2024.
Posted on 11 February 2023 in 800V, Batteries, Electric (Battery), Market Background | Permalink | Comments (25)
I typed into google advanced search: ' What are battery monitoring cables made of?'
And the answer came back as 'solid copper'
' Once the cables connected to the BMS are removed, the vehicle weight is reduced by 66~198Ib.'
Is even more exciting than it sounds, as copper is a major expense and critical material for EVs, in somewhat short supply
Posted by: Davemart | 11 February 2023 at 03:41 AM
The 66 to 198 lb weight reduction is typical marketing hype. Balancing between cells can be done with a reasonable small gage wire. 20 AWG wire is 0.0048 lb/ft ( https://www.wireandcableyourway.com/20-awg-hookup-wire-ul-1007-1569-10-strand-tinned-copper-500-or-1000-spool ) or 4.8 pounds for 1000ft.
A Nissan Leaf had ~ 96 cells in a 400 bolts system, so if each cell had 3 foot long leads on average and a wire was shared when two cells connected in series, that is 300 feet or under 2lb in wire.
Posted by: Dave C | 11 February 2023 at 06:27 PM
Way above my pay grade, but is seems others have very different figures to yours, as well as LG Innotek
Here is an article in 'Electronic Design' who presumably are not totally dumb on the subject:
https://www.electronicdesign.com/markets/automotive/article/21152534/electronic-design-wireless-bms-for-evs-reduce-weight-simplify-design-maximize-performance
' A wired battery-management solution, however, has several challenges associated with detecting failures. Among them is the cost of repair and bulky cables weighing anywhere between 75 pounds on the low end to about 150 or even 200 pounds. '
And here is Texas Instruments:
https://www.ti.com/lit/ml/slyp691/slyp691.pdf?ts=1676193253247&ref_url=https%253A%252F%252Fwww.google.com%252F
On page 12, they say that a BMS takes more than 3 miles of cable, so around 50 times your 300 feet, which using your 2 lbs for that comes out to 100 lbs or so.
As I said, above my pay grade.
Posted by: Davemart | 12 February 2023 at 01:34 AM
I've just given myself a headache trying to look in a bit more detail at BMS.
There are a wide variety of topologies, centralised and distributed, which may help to explain differences in potential wiring requirements:
https://www.synopsys.com/glossary/what-is-a-battery-management-system.html
The requirements for HV systems as needed by most EVs are also far more onerous than for LV systems:
https://www.instructables.com/Battery-Management-System-Introduction-to-Hardware/
Posted by: Davemart | 12 February 2023 at 03:56 AM
Davemart: A typical HV-battery in a BEV is comprised of x-no. of cells switched in series and parallel modes. Theoretically and practically, every cell has a different internal resistance. IAW with Ohms law ( R = V : A [R= resistance, V=voltage, A=amperes/current]), the current flowing through a complete branch of series switched cells is determined by the total resistance of this branch. Therefore, the voltage drop-off of every cell differs IAW the internal resistance of that cell. The resulting problem is that the charging level of every cell differs accordingly. The purpose of a BMS is to adapt the true internal resistance of a cell to an apparent resistance that is equal to all cells. This assures that all cells are equally charged to their full capacity despite their differing true internal resistance. This problem applies to series switched cells only and not to parallel switched branches. Therefore, the current that must be compensated is the current difference flowing to each cell and not the complete current. This current difference is relatively low compared to the total current flow to charge all cells. This balancing current needs only relatively thin wires to accomplish this task without noticeable voltage drop-off. Therefore, there is absolutely no need for arm-thick copper strands weighing eye-popping kg's as noted in the article.
Posted by: yoatmon | 12 February 2023 at 07:29 AM
From my limited understanding of the figures given, the discrepancy between Dave C's figures for the cabling needed and that of Texas Instrument's and other's figures is explained by the length needed, of the order of 3 miles against 300 ft, not the thickness.
Posted by: Davemart | 12 February 2023 at 09:22 AM
Here is a link claiming that the battery pack in Bolt has copper amounting to 8% of the weight of the pack, so around 72 lbs out of 906lbs:
https://www.visualcapitalist.com/how-much-copper-is-in-an-electric-vehicle/
I assume that that is the wiring.
Posted by: Davemart | 12 February 2023 at 09:32 AM
There seems to be good support for the argument that the use of copper in BMS is radically overstated here:
https://lmc-auto.com/news-and-insights/will-bevs-really-drive-demand-for-more-copper/
3% of the copper use in the battery is in the BMS in the 1st generation Jaguar IPace, they reckon!
Sounds tough to save 60 odd kilos of battery weight by a wireless BMS then!
Posted by: Davemart | 12 February 2023 at 10:07 AM
You must differentiate between the copper needed for the main load and that necessary for the balancing of the charge difference for the individual cells. You need bigger lead cross-sections if you are charging e.g. with 200 kW than 7.2 or 11 kW. Low copper cross-sections at high power charging result in enormous heat losses. The balancing current for the cells is far lower than that actually occurring for the charging current. I haven't repaired any HV-batteries for BEVs but plenty for lawn mowers, e-bikes, and scooters. The copper cross section necessary for balancing power is a small fraction of that necessary for the charging power. I would say that the article above is a "bit" exaggerated. The cylindrical cells used in battery packs for BEVs are the same as those used in the items I mentioned.
Posted by: yoatmon | 12 February 2023 at 10:12 AM
It certainly sounds as though Innotek and Texas Instruments are being a tad 'optimistic' about the potential weight savings of wireless BMS, and by extension, copper!
Posted by: Davemart | 12 February 2023 at 11:34 AM
@Davemart Thanks for the TI reference. This is not marketing hype. The value of a wireless BMS is much more than just copper replaced. Wiring connections between the BMS and the battery cells (could be cylindrical, prismatic, or pouch) are made of a variety of materials. Reduction of weight is just one benefit: cost, reliability, safety, multiple points of failure, etc Wiring harnesses are a labor intensive, constant headache for all auto manufacturers (this includes all automobiles not just EV). GM already uses wireless BMS and others will follow like LG https://news.gm.com/newsroom.detail.html/Pages/news/us/en/2020/sep/0909-wbms.html
Posted by: Gryf | 12 February 2023 at 12:21 PM
I'd agree that there are other potential benefits of wireless BMS aside from weight savings, and I should point out that it was not Innotek who claimed major savings on copper, but was an extrapolation I made from their weight savings claims, as I figured most of it had to be comprised of copper.
Another caveat is that since there are loads of topologies for BMS, perhaps they are talking about some particular configuration.
But taking all that into account, I can't see how they get to:
' Once the cables connected to the BMS are removed, the vehicle weight is reduced by 66~198Ib. Removing the dozens of cables and connectors required for a BMS reduces both the weight and volume of a battery pack.
This secures additional space of 10~15% for a battery pack, enabling increasing the capacity of a battery, and hence, the range of an EV. It has been confirmed that a wireless BMS increases the mileage of an electric vehicle by up to 12 miles. '
Maybe they are just blowing smoke, but it is interesting to try to figure out exactly what, if anything, they could have based that notion on.
Posted by: Davemart | 12 February 2023 at 02:03 PM
@ Davemart: I've been tracking Quantumscape (QS) and GMG for quite some time now. Qs's SS tech platform is in my estimation unparalleled. On the other hand, GMG's chemistry is more appealing to me than that of QS. QS has claimed that their tech platform is compatible to other chemistries. https://www.quantumscape.com/resources/blog/lithium-iron-phosphate-on-the-quantumscape-solid-state-lithium-metal-platform/ GMG's chemistry enables charging times 60 to 70 times faster than conventional Li-ion. Presently, GMG have achieved a volumetric energy density of ca. 310 Wh with their solution and that with only exploiting one of the three potential valence electrons. Aluminum has three valence electrons but Li only one. QS is banking on Li for their cathode material. What I would sincerely appreciate is that QS and GMG cooperate together to merge the tech platform of QS and the chemistry of GMG. GMG is diligently involved to employ all three valence electrons of Al in a future variant.That would raise the energy density of the cell to at least a staggering 930 mAh. Such a solution would eliminate a BMS and necessary wiring completely. Li is not a rare - but a scarce element which is found in relatively few locations worldwide. On the other hand, Al is the most abundant metal element in the earth's crust everywhere and is far cheaper to access and to recycle than Li.
Posted by: yoatmon | 13 February 2023 at 03:39 AM
@Davemart - working in the repair field I think the weight savings estimate is more whole system vs only the copper or harness.
If you go to wireless BMS, then you need no winging into/out of the pack to rest of car. The BMS can be internally powered (its sitting on a battery!). No more CAN buss pairs for every BMS, on every cell, combined into every module, all wired to external interface. Imagine if we remove the main plug with dozens of terminals and only had the main current carrying cables. It is balance of system that contributes to overall weight savings. => Remove case bracing for access hole for harness connector, structure for harness routing thru and to outside of battery case, support structure for some modules (to consolidate CAN buss from multiple BMSs into central BMS control module to rest of car)
Now, as many times as my radio or cell phone have problems with interference and loss of signal, I would be hesitant for my BEV to suddenly stop because jamming interference (intentional or accidental) caused one or more BMS to go off line. Can't properly charge the battery or use power out of it if you don't know the condition of the cells. System won't risk a Lion thermal event and shut the car down because BMS stopped talking.
Posted by: Variant003 | 13 February 2023 at 07:50 AM
930mAh would certainly be great to have, and bring into view more practical battery powered flight and so on. But: ' Such a solution would eliminate a BMS and necessary wiring completely.' I don't follow you at all. Why would increased energy density eliminate the need for a BMS? You still need to know what is going on in each cell, and so on.
Posted by: Davemart | 13 February 2023 at 08:17 AM
A very interesting and very plausible, so far as my severely limited education on the subject goes, analysis.
I did not think that they had simply added a couple of noughts to potential weight savings, and that there was likely some path through to the kind of savings they suggest.
As for the perils of wireless, I am entirely of your way of thinking. I always keep a wired mice and keyboards in a drawer, ready for when the connection gets temperamental.
With a wireless BMS, it would appear that in the event of a problem, you simply have a very weighty and bulky brick in your car.
Posted by: Davemart | 13 February 2023 at 08:22 AM
@ Davemart: Without a BMS you couldn't charge every cell to an optimal maximum limit and lose somewhere between 5 to 10% energy density and impact range. In order to achieve max. range you must ensure via a BMS that all cells are charged to their full potential. With the high energy density that could be achieved as stated in my previous post you could easily waiver those 5 to 10% and simplify the charging procedure without a BMS.
Posted by: yoatmon | 13 February 2023 at 09:54 AM
@ Davemart: I can follow the argument that variant003 supplied. The interference problem could be detoured by installing a can-bus system and thus eliminate all the wiring and the interference problem. But GMG's Graphene-Al cell based on the QS tech-platform would eliminate all those possible problems and would be cheaper to boot.
Posted by: yoatmon | 13 February 2023 at 10:13 AM
' With the high energy density that could be achieved as stated in my previous post you could easily waiver those 5 to 10% and simplify the charging procedure without a BMS.'
Depending on the price per Kwh, it seems unlikey to me that capacity will simply be used as a reserve to enable no BMS. In the event that someone did charge to the full capacity nevertheless, it would seem that the battery might then be dangerous in any case.
Posted by: Davemart | 13 February 2023 at 12:41 PM
"In the event that someone did charge to the full capacity nevertheless, it would seem that the battery might then be dangerous in any case." That would certainly be the case for Li-ion but not for Graphene-Aluminum.
Posted by: yoatmon | 14 February 2023 at 03:20 AM
https://www.newsfilecorp.com/release/140087/GMGs-Battery-Update-Significant-Battery-Performance-Cell-and-Graphene-Production-Improvements
Posted by: yoatmon | 14 February 2023 at 03:30 AM
I have had a look at your link, but did not find anything there to substantiate your argument that:
' In the event that someone did charge to the full capacity nevertheless, it would seem that the battery might then be dangerous in any case." (My point) That would certainly be the case for Li-ion but not for Graphene-Aluminum.(your reply)
Posted by: Davemart | 14 February 2023 at 10:46 AM
@yoatmon It does appear that Aluminum Ion Batteries have a future due to many factors, e.g. material abundance, volumetric energy density, etc. Unfortunately, it appears that they will not be in production very soon. Also, Not sure how relevant GMG Graphene Aluminum Ion batteries are to wireless BMS either. If you like here are two references that go much deeper than the GMG Graphene Battery Update. “Cathode choices for rechargeable aluminium batteries: the past decade and future”, Chengzhong Yu - University of Queensland, (works with GMG) https://matlab.labapress.com/article/doi/10.54227/mlab.20220055 This article does not cover Aqueous aluminum ion batteries. An American company, Alsym Energy (https://www.alsym.com/about/) does and uses a Manganese Oxide Cathode. Their CTO is Dr. Rahul Mukherjee. He is the inventor on this patent https://patents.google.com/patent/US10978734B2/en?oq=US10%2c978%2c734B2 It is assigned to Everon24 - an Alsym Energy company.
Posted by: Gryf | 14 February 2023 at 05:19 PM
@ Gryf: I've `digested' the complete article which you referenced:(https://matlab.labapress.com/article/doi/10.54227/mlab.20220055) "However, its overall performance was hindered by two major problems using Al as an anode. First is the formation of a passivating oxide layer in an aqueous environment, reducing the operating voltage and increasing both charge and mass transfer resistance." QS employs Al as the cathode; the solid state electrolyte completely detours any aqueous detrimental influence. Surely there are many obstacles (ifs) that must be overcome to arrive at an usable product. What is particularly appealing to me is the tech-platform of QS. Their cell, as you probably know, has no anode only a cathode; the anode is generated during the charging process. IF the claim of QS that their tech-platform is valid for other chemistries as well then GMG's chemistry could benefit from it. IF the solid electrolyte employed from QS does not hamper the intercalation process then the high charging speed of GMG's chemistry solution would remain unaffected; a 3-D graphene covered copper strip would do fine for the deposition of the Al-ions. IF QS manages to employ all three valence electrons instead of only one as is, then the energy density would be far beyond the limits of Li. If, If, If... I'm only theorizing and cannot prove experimental results which are important as final proof. I retired twenty years ago and am no longer in a position to experiment but nevertheless I,ve managed to keep distance to the borders of senility.
Posted by: yoatmon | 15 February 2023 at 04:08 AM
Whilst roaming in the Internet, I stumbled across this interesting report from a Munich research facility. https://phys.org/news/2023-02-solid-state-battery-material-class-excellent.html The frustrating part about it is that they are messing around again with Li. Why don't they experiment with Al?
Posted by: yoatmon | 15 February 2023 at 07:17 AM
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