Bosch Bets on 48V Mild Hybrids

Discussion in 'In the News' started by xcel, Nov 24, 2017.

  1. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    [​IMG][​IMG][​IMG][​IMG] One more chance, maybe the last chance, for mild hybrids to proliferate.

    Wayne Gerdes – CleanMPG – Nov. 23, 2017


    Bosch’s new 48V battery for mild hybrids will soon be reaching automakers across the globe. OEMs can also eliminate the expensive R&D to create a similar system from scratch. This means that installation of the Li-Ion battery and small but robust motor will benefit compact through microcars. Production of the battery is scheduled to start in late 2018. Anticipating a large market for entry-level mild hybrids, Bosch offers other powertrain components for these models in addition to the 48V. The company estimates that some 15 million 48V hybrid vehicles will be on the road by 2025.

    Automakers in China, Europe, and North America are focusing on CO2 emission reductions. According to Bosch, the yet to be produced 48V battery is already in high demand among Chinese manufacturers, and the Li-Ion unit is poised to become a global success. Bosch is already in talks with over a dozen customers and has secured a considerable number of production projects.

    The secret of the battery’s success is its inexpensive way to reduce vehicle CO2 emissions. The battery requires no active cooling and its housing is made of plastic, not metal. Both bring costs down. The plastic housing presents a challenge, as Li-Ion cells expand when the battery is charging and over the course of the battery life. As a result, the housing must withstand a certain amount of stress.

    Bosch. invests $475 million USD/year in electromobility with more than 30 production projects, including in the manufacture of batteries, that are in current production.

    The affordable 48V hybrid for the mass market provides the ability for every powertrain to become a hybrid drivetrain. Bosch expects its battery to find success in not just China but Japan and Europe as well.

    Bosch 48V Li-Ion Q&A

    How does a 48-volt hybrid save on fuel?

    A 48V hybrid can reduce fuel consumption through the use of a regenerative braking system that stores and then doles it out to a small motor to help accelerate the car back up to speed.

    Why is China seen as an e-mobility pioneer?

    With more than half a million models sold, China is by far the world’s largest market for electric vehicles. It is a world leader in e-vehicle production, too. Electric vehicles and hybrids are set to take over still more of the Chinese market, especially with government support.

    Why is the new battery efficient when it comes to CO2?

    No other country in the world emits as much CO2 into the atmosphere as China. It has set itself a fleet target of 117 g/km by 2021, and China’s automakers are looking to the 48-volt hybrid system to help them achieve this goal. Bosch’s new and less expensive 48-volt battery will make the system more affordable for a broader market, and will thus help Chinese automakers considerably reduce CO2 emissions.

    I just do not see the market for a 48V system when 250 to 650V systems use mostly the same components albeit larger in every respect and offer far superior efficiency gains. There are savings in the downsized components but is Bosch reinventing the wheel with a smaller wheel and trying to gain something from it? Then again, a mild hybridized drivetrain is certainly more efficient than one that is not hybridized at all?
    BillLin likes this.
  2. Jay

    Jay Well-Known Member

    There are a lot of plusses with a 48V electrical system, even for non-hybrid vehicles. It reduces current for the same amount of power which means smaller wires and less copper in the car. It allows manufacturers to integrate the starter and alternator. There's a ton of 48V conversion electronics from the telecom industry that could work in cars right off the shelf. 48V is enough voltage to make a big improvement in efficiency while still being low enough not to shock people--even if they are standing in water. The question is: Why have we not yet made the switch? I've been reading about it in engineering journals for many years yet we still live in a 12V automotive world.
    BillLin and xcel like this.
  3. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    We have been waiting for it for over a decade now and the legacy systems continue to override. With the lower power 12V auxiliaries available today, I do not see much need to change.

    Trollbait and BillLin like this.
  4. MPG Mom

    MPG Mom Member

    The biggest draw to 48v systems is that it's more powerful than a 12v system for things like mild hybrids and electrified forced induction (direct electric, or assist to reduce turbo lag), but the voltage is low enough to still be considered low voltage. This means that wiring can be far less insulated and far less costly than 300v systems.
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  5. SI_Prius

    SI_Prius Well-Known Member

    Small battery in a plastic case without cooling, I wonder how many times the system won't use the battery because of overheat?

    This system will fit nicely in beating the test cycle, but we will see how it copes with real driving scenarios.
    xcel likes this.
  6. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    I would expect there NOT to be a 12V battery to save cost and weight. (I understand there may be an issue and cost associated with providing 12V all the time; perhaps this is already provided by the 48V system; I have not read the specs) Perhaps cost is also the main reason 48V systems have not made greater inroads. 12V is so darn cheap and plentiful. Start/stop systems would likely work better on 48V vs 12V.

    Edit: I forgot why I was replying... :D I doubt there is an option for the 48V battery to refuse to work due to heat. The engineers have to make that 'bulletproof' at least to the same level as the current 12V batteries.
    Jay and xcel like this.
  7. SageBrush

    SageBrush Active Member

    I thought the GM mild hybrids were 48v.
    If so, then I wonder how the Bosch will be better than the ill-fated and *very* mediocre GM products

    OTOH, at least the Europeans can look forward to somewhat better stop/start system. They need it for pollution control in the cities
    Or maybe this is just insight into the grand VW plans for electrification.
    xcel and BillLin like this.
  8. Trollbait

    Trollbait Well-Known Member

    It also means you can move some accessories, like the water pump, away from engine driven, and also introduce catalytic convertor heaters to reduce start up emissions.
    I think these systems will still use 12V accessories. Probalby too costly to go 48V for all at this time.
    How often does a Ford Energi or Prius Prime switch to hybrid mode because of battery overheat? I haven't seen any in depth technical specs on the system yet to say if it has no cooling.
    The first BAS system was only 36V. Costs were too high at the time for any mild hybrid to be a success.
    The first eAssist had a 15kW motor and 115V battery. Making it about as powerful as the IMA of the time.
    The second eAssist dropped in power to 10kW with a battery about the third of the Malibu hybrid's in capacity. It should be cheaper to put into a car now. Keeping it at or under 48V will help on the cost side.

    A system like Bosch's or Continental's should only add $800 to $1200 to the car's price vs. a full hybrid's $2000+. The car manufacturers are looking at them more to lower emissions than get a big improvement to fuel economy.
    xcel and BillLin like this.
  9. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    I can't answer that question, but I can say that I've heard the fan run while charging and after one of the rear seat air ducts was unintentionally blocked. :D So at the very least, there's active air cooling going on in both Ford and Toyota plug-ins. I agree that liquid cooling would be better, but perhaps the cost and complexity is much greater? Given the 3.3 kW or lower charge rates on these Ford and Toyota plug-ins, I'd say the heat from charging isn't as great as that on the full 6.6 kW level 2 (e.g. Chevy Volt and Nissan Leaf) or fast charging systems. Heck, with this 1/2 power L2 charging, I don't find the speed improvement of L2 charging worth it for these Fords and Toyotas, especially if you have to sit and wait for the charging. Things work fine with overnight charging at 110V...
    xcel likes this.
  10. Trollbait

    Trollbait Well-Known Member

    For PHEVs with EV ranges of the Energis to Hyundai models, air cooling is fine. The lower cost out weighs the need for a larger pack and lack of heating control. Besides, they are hybrids. The rare times to pack gets too hot, you can't use EV mode, and the ICE comes on. It's EV mode draw that is the main generator of heat.
    The Volt has a 3.7 or something charger, but you could have meant Bolt.
    For home charging, L2 is more efficient than L1; less loses. It also might be needed for preconditioning the car's cabin. L1 can do that or charge, but not both at the same time.

    Back to the 48V systems, I expect temperature management was considered during development, and can't say much about it from a single picture. The case might actually be metal, or there could be duct ports out of sight.
    xcel and BillLin like this.
  11. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    More on the Continental 48V Belt Starter Generator System


    Continence jumps into the 48V Mild Hybrid fray...

    When coasting to a halt for a red light ahead, the engine in the all-new 2019 Audi A8 shuts down at 14 mph, much earlier than with a conventional stop-start system. The engine also shuts down periodically during steady-state cruising at speeds between 34 und 99 mph, restarting instantly when the driver wants to accelerate. During braking, a large percentage of brake is recovered by conversion into electrical energy and stored in a 48V Li-Ion battery for future use. All come together thanks to the compact belt starter generator with integrated power electronics. The system replaces a conventional starter pinion and is driven by a belt connected to the engine crankshaft.


    With a starter output of 8 kW (almost 11 hp) and peak transient torque of up to 44 lb ft., the asynchronous motor has a continuous power rating in generator mode of up to 5 kW, with peak output of up to 15 kW available for short periods. This is made possible by a water-cooling system that protects the motor and power electronics from overheating. The coolant is supplied by the regular engine cooling system eliminating the need for a second, low-temperature cooling circuit.

    The combination of zero-emission coasting, earlier engine shutdown by the stop-start system and improved braking energy regeneration results in fuel savings of up to 10 percent per the NEDC. I remain a skeptic we will see this level unless the engine was downsized or significantly atkinsonized and I am not seeing downsizing.

    The 48V system makes it possible to provide four times as much electrical power and clears the way for adaptive suspension systems like that in the all-new 2018 Audi A8.

    2018 Audi A8

    The Continental 48V Belt Starter Generator is standard.​

    Continental has been producing the belt-starter-generator with integrated power electronics on highly automated production lines at its Nuremberg plant since last year. The system is based on a modular concept that can be adapted to meet the needs of all automakers. For example, Audi’s emphasis on high performance has been met by increasing the length of the stator, which instead of windings consists of welded copper rods. The collaboration with Audi was not just limited to the hardware.
    BillLin likes this.
  12. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    In a related story , a new Bentley model features an engine that will shut off periodically during steady-state cruising , then the driver is allowed to PEDAL the car for a while to get outstanding efficiency without any
    harmful diesel exhaust. Those one percenters LOVE their fitness ! But how does the VAG dealer here in the states tell the guy who just bought a $100K Audi that it's "normal" for the engine to shut down like that ?

    This is a baby-step towards a "real" HEV.
    BillLin likes this.
  13. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    I haven't seen that news about a Bentley, Edwin. Is it April already? :)

    How about THIS Bentley?

    "Blower Bentley Pedal Car
    Sold For $9,200
    Identification No.

    57 in. long

    This Bentley was produced by Little Pedalers, and it is nicely equipped with features that contribute to its smart appearance. Wooden running boards assist with entry into the car and provide storage for the Shell Car Care Kit and side-mounted spare. Leather hood straps, a dual windscreen, a side mirror, and a Bentley badge are further period details found on this pedal car. Working headlights and a vintage-style vehicle registration badge complete the look."

    EdwinTheMagnificent likes this.
  14. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Yeah , THAT was what I was thinking of, lol.
    BillLin likes this.
  15. Jay

    Jay Well-Known Member

    Wow, 8kw! The starter on my Acura RSX is only 1.2kw.
    xcel and BillLin like this.

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