How to interpret Tesla’s Battery Day lingo





Confused by kilowatts? Can’t inform an anode from a cathode? Right here is a straightforward information to the jargon more likely to be tossed round at Tesla’s Battery Day on September 22.


A Tesla Mannequin three makes use of a single lithium-ion battery pack that homes 4 smaller modules. Every module incorporates 700 to 1,000 particular person cylindrical cells, formed very similar to those in a flashlight.

Cells can come in numerous sizes and styles, however most have three key parts: Electrodes, electrolyte and separator.

Electrodes retailer the lithium. The electrolyte carries the lithium ions between electrodes. The separator retains the constructive electrode from coming in touch with the damaging electrode.

Power, within the type of electrical energy, is discharged from the battery cell when lithium ions movement from the damaging electrode, or anode, to the constructive electrode, or cathode. When the cell is charging, these ions movement in the wrong way, from cathode to anode.

Panasonic provides cylindrical battery cells to Tesla for the Mannequin three and Mannequin Y. The constructive electrodes are produced from a mixture of nickel, aluminum and small quantities of cobalt, known as NCA.

In China, CATL provides Tesla with battery cells in a flat format known as prismatic, with a distinct cathode combination (lithium iron phosphate, or LFP). This materials incorporates no cobalt and is inexpensive than Panasonic’s NCA chemistry, however doesn’t maintain as a lot power or present as a lot vary because the NCA cylindrical batteries of the identical dimension or mass.


In electrical autos, energy is expressed in kilowatts (kW) whereas power is expressed in kilowatt-hours (kWh).

“To have nice acceleration in an EV, you’d need excessive energy density. To have lengthy vary, you’d need excessive power density,” mentioned electrochemist Leah Ellis, co-founder of Elegant Programs.

Tesla’s subsequent technology of batteries is anticipated to have the ability to retailer extra power — and thus allow higher automobile vary — whereas offering extra energy.

As a result of LFP battery cells usually can not retailer as a lot power as NCA cells, autos that use LFP cells usually require extra of them to attain the identical vary between costs as autos powered by NCA cells.


Tesla autos at present can drive as much as 400 miles between costs with NCA cells and almost 300 miles with LFP cells. Tesla has mentioned the brand new Cybertruck will stand up to 500 miles.

Tesla’s subsequent technology of batteries is anticipated to have for much longer life: The equal of 1 million miles or extra, in contrast with about 500,000 miles at present.


The price of battery cells and packs is coming down quickly. Measured in {dollars} per kilowatt-hour ($/kWh), consultants have pegged $100/kWh on the cell degree as the purpose the place electrical automobiles will start to method the price of autos powered by combustion engines and fossil gasoline.

A lithium ion battery cell that prices $100/kWh to supply means a battery pack, with its further battery administration system, cooling system and different supplies, may price $125-$130/kWh or extra.

Immediately’s battery packs price round $10,000-$12,000, relying on their capability. Tesla is aiming to cut back the price of future packs to lower than $6,000, which might put the cell price at effectively below $100/kWh.

First Printed on Sep 21, 2020 03:45 pm


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