Battery Info

Battery technology advances have been the primary reason EVs are now considered not just a viable alternative to ICE vehicles, but also an inevitable full transition. As when LCD flat panel tvs came out with price tags of $16,000 (on sale from $20,000 msrp!) many of us laughed at first without seriously thinking through the potential for advances in technology and improvements in manufacturing (basically the competition effect on a product that everyone owns). Using expensive laptop batteries to run a car? Sounded a bit like a scam. Of course, then those batteries worked, and they provided features unique to EVs, and they dropped in price...and people bought the cars. Just like what happened with LCD TVs.

Of course, battery technology had many hurdles. Early batteries caught fire much too easily...chemistries had to be changed in those 18650 batteries, and isolation logic had to be added to prevent quick spread of fires in accidents, and batteries needed to properly managed to prevent both overcharge and complete drain situations. Also battery life had to be improved. This involved adding thermal management to keep batteries properly cooled or heated when charging and discharging. This also involved improving battery chemistries and battery pack designs. And of course there was cost. Over the last ten years battery prices dropped from $1,100 per kwh to near $100 per kwh today, making possible $35,000 cars with over 250 miles of range as early as 2019.

Advances in motor technology and even transmission design along with reducing weight and drag coefficients in vehicles also helped with battery related mileage (miles per kwh) tremendously. Here is a presentation on motors and drive train in the Tesla to give you and idea of the technology.

Recycling

Large lithium ion battery packs have only in the last few years just started to transition from reuse and repair to recycling. These large packs will contain either pouch style packs like the Bolt uses or cylindrical 18650 or 2170 cells like Tesla uses. The Tesla Model 3 LR has 4,416 of the 2170 cells pictured earlier in a pack...the pack consisting of 4 modules of 1,104 batteries each. These batteries are glued into a rigid structure including coolant tubing so you can imagine some of the complexities of reusing or recycling individual cells. Since batteries in modern EVs last into the 300,000-500,000 mile range and newer LFP batteries and the 4680 batteries are expected to last double that range or more, there actually haven't been a lot of batteries to recycle...mostly scrap during manufacturing and test as well as accident returns. By the 2030 timeframe that all will change and the need for recycling will ramp up through 2040.

As a result, Tesla has been a proponent of having the battery and battery pack manufacturers be responsible for recycling their own batteries, ideally at the same locations that manufacture them. This makes sense for many reasons, 1) they can immediately reuse the materials they extract to make new batteries (Tesla just started recycling at their Nevada Battery giga factory late in 2020, but in less than a year reclaimed 1,300 tons of nickel, 400 tons of copper, and 80 tons of cobalt, along with other materials), 2) the manufacturer knows how the batteries and packs are manufactured and what holds them together so know how to take them apart, 3) they have incentive to improve the build process in ways that aid in the unbuild process, and 4) they keep everything in one spot so they aren’t shipping battery scrap and extracted metals long distances (batteries are heavy). Currently Tesla is recycling all their batteries in the US and starting or planning recycling facilities at their overseas plants. Other battery companies have started building large recycling plants as well. A good example is Hydrovolt.

Wrights Law

And don't forget Wrights Law. From the TV transition to LCD and Incandescent lightbulbs to LED and before that cell phones drastically becoming affordable (way back before smart phone companies got greedy) and even before that as PC prices dropped from astronomical to hard to sell for $10 at a garage sale...all of these were examples that followed Wrights law very closely. Basically due to cost savings as manufacturing scales up and refines the process (a good example is Tesla Model Y going to a structural battery pack and gigapressed front and back subframes early next year, reducing over 700 parts into 3 parts and putting 100s of robots out of work in the assembly process 🙂), but also as competition drives the profit costs down somewhat.

Energy Density

But, what about energy density? Battery energy density is a good measure to compare different battery technologies that can be used in EVs, but is a misleading figure when comparing EVs to cars using other fuel technologies (ie gas or hydrogen fuel cell vehicles). The reason is a combination of efficiency and looking at the issue from a system level. The argument usually goes: gas is more energy dense (33 kwh per gallon of gas) than a battery technology can ever achieve per weight or volume, so that is a disadvantage EVs need to overcome.

In actuality, there are no disadvantage to overcome. First, gas cars are very inefficient users of that 33 kwh of energy...typically at 20% eficiency, taking that usable energy density down to 6.6 kwh with the rest going out as heat in the tailpipe and friction in the moving parts. EVs are over 90% efficient in the use of energy stored in their batteries and the electric motors are simply more effective at using that energy, using no energy to move when coasting or stopped in traffic and recovering energy when stopping or going downhill.

Second, the system level view is important to keep in mind as well. My 460 HP Tesla Model 3 has a 1,000 lb battery pack that sits entirely under the floorboard of the car (a little over 4" thick.) The EV is missing a full 16 gallon gas tank and all the support pumps, structrual supports, piping, etc related to the tank, missing a 475 lb comparable engine (tesla motors are around 70 lbs), missing all those extra gears (single speed non shifting drive train with motor right at the wheels), missing all those pullies, belts, alternators, etc as well (its a really long list). As a result, a comparable sports car to my Model 3 (ie a 2020 bmw m3 g80) will 1) weigh almost the same as my EV, 2) have the same range fully fueled with 16 gallons of gas as my EV (my 75 kwh giving same range as the power in just over 2 gallons of gas if you recall the numbers above), and 3) in answer to the volume density argument, the Tesla has massively more internal space for storage than a comparable sports car like the M3...a massive rear trunk, a sub trunk where a gas tank would normally be in a gas car, and a front trunk where the engine in a gas car would be, plus no hump in the car so more legroom for 3 passengers in the rear seats and massive amount of space to store stuff in two large center console spaces.

As technology improves (for example with the new 4680 batteries and switching to a structural battery pack), the car will keep reducing weight, making the mpge go up. Currently the electricity to drive my EV 40 miles costs $1.00 at 10 cents per kwh...50 miles in city driving. That same $1.00 worth of gas will drive the BMW M3 just under 7 miles at $3.00 per gallon.

Recycling Update