Tesla, and its range of electric vehicles has proven to be a major disrupter to the world’s auto industry. With the introduction of the mainstream and relatively affordable Model 3 in 2017, the company has continued to prove that electric vehicles (EVs) can be both practical and fun to own and drive. The success of the Model 3 has other car companies scratching their head and wondering how Tesla has managed to build a desirable EV that is also profitable.
Sandy Munro has presented a webinar detailing his company's tear-down of the Tesla Model 3 battery pack. (Image source: Munro & Associates)
As a way to begin to answer that question, Munro & Associates, located in Auburn Hills, Michigan has disassembled a Tesla Model 3. In a 60-minute Design News webinar, automotive engineers Sandy Munro and Mark Ellis of Munro & Associates take their audience through a teardown of the Model 3 battery. Details about the pack’s design, construction, cooling system, and cell technology, among other key areas are discussed. Munro uses photos and technical descriptions of virtually every component to provide an in-depth look at the Model 3’s battery system. They also explain how Tesla’s battery compares to the batteries of its closest competitors, the Chevy Bolt and BMW i3. The webinar is sponsored by ROHM Semiconductor and Vertex. The webinar can be found here.
The Tesla Model 3 battery pack consists of 4,416 lithium ion cells in the 2170 cylindrical configuration. The pack has two sets of modules. One set has 23 bricks made up from 46 cells per brick and the other set of modules has 25 bricks made up of 46 cells per brick. The pack produces nominally 350 volts. The cylindrical cells provide a weight advantage. “Tesla using the cylindrical batteries does not have the weight disadvantage that the BMW i3 and Chevrolet Bolt have,” Munro’s Ellis said.
Munro has found that the Model 3 battery pack has some interesting features that distinguish it from the battery packs used by other manufacturers. The high-voltage electronics are centrally located close to the battery, which allows less-expensive bus bars to carry the high voltage and current levels—significantly cheaper than the heavy electrical cables that most other competitors use to carry electrical energy to separated high-voltage components.
The bus bars have another potential advantage. “They are doing everything possible in this vehicle to eliminate, neutralize, any kind of vibration in the battery pack, the electronic systems that are related to the battery and these flexible buss bars I believe are one of the things that they use to help dampen any kind of vibration in the control circuitry,” said Ellis. Tesla also uses a thermally-conducting foam blanket that covers the individual cells to help prevent vibration.
In tearing down the Tesla Model 3, Munro & Associates have found a variety of instances where engineers working on different parts of the car clearly cooperated with one another to produce a superior product—something that is not always evident in vehicles built by other car companies. “Tesla has got a cultural thing going on, not just a technology thing,” noted Sandy Munro.
A Live Presentation
In addition to the webinar, if you want to know more about how Tesla compares to its competition, Munro & Associates will display two completely disassembled electric motors; one Tesla Model 3 internal permanent magnet (IPM) and one Jaguar I-PACE IPM, at The Battery Show and Electric & Hybrid Vehicle Technology Expo 2019, in Novi, Michigan, in a talk presented by Cory Steuben, Account Director at Munro & Associates. The intent of the 25-minute forum is to dive into the key differences between the executions of the IPM motor designs. Steuben will highlight the key differences in the geometry of the rotor and stator, the placement and retention of the magnets, and specific details about the magnet material compositions and manufacturing processes. He will be prepared to answer detailed questions concerning the skew angles, fill-rates, and material compositions of the various rotor and stator parts components.
The talk is titled “Tesla Model 3 vs. Jaguar I-PACE Motor Insights” and will be presented on Tuesday, September 10th from 10:15 AM-10:40 AM.
Although EVs presently account for just 1-2% of the US market, there may be indications that electrification is gaining both public awareness and acceptance. Webinars and presentations by companies like Munro & Associates bring greater understanding of the engineering behind vehicles from Tesla, widely acknowledged to be the EV leader. Bringing such information to light will help other automakers improve their EV designs, or more effectively enter this expanding market.
Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.