The Octovalve is a coolant switching valve that Tesla's patent defines as a valve with eight ports. A rotating part inside the valve switches the paths that connect the battery, the drive units, the radiator, the chiller and more. Patent US11932078B2 (granted March 19, 2024) contains this definition. But we could not confirm the whole system's behavior in real cars, or any efficiency figures, in official Tesla materials.
In an earlier article, how heat flows in an electric car, we saw how heat moves around the car. In this article we look at the part that switches that flow, the Octovalve, checking against patents.
The conclusion: the Octovalve is an eight-port valve that switches coolant paths
Tesla's patent US11932078B2 says this.
"the valve includes 8 ports and is referred to as an octovalve"
"Octo" means eight. A port is an inlet or outlet for coolant.
According to the patent, the valve has a housing and a rotating part inside it (the stemshell). The stemshell has channels that connect ports to each other, and rotating it changes which ports are connected.
What does it connect?
In the patent's description, the Octovalve can be connected to parts such as these.
- The battery (supply and return)
- The drive units (the loop that cools the motors and so on, and a pump)
- The liquid-cooled condenser (LCC) (a part that passes refrigerant heat to the coolant)
- The radiator (a part that exchanges heat with the outside air)
- The chiller (a part that exchanges heat between refrigerant and coolant)
It uses them differently by changing how they are connected.
Examples of connections (from the patent's description)
Patent US12365215B2 (in the same family) describes several "modes."
| Mode | Content (a paraphrase of the patent) |
|---|---|
| All in series | The battery, drive units, LCC, radiator and chiller form one loop |
| Ambient source | The radiator takes heat from the outside air into the chiller, and the LCC warms coolant for the battery |
| Radiator bypass | The radiator's inlet and outlet are connected directly, so there is little or no flow through it |
| Parallel | The radiator with the drive units, and the battery with the chiller, form separate loops |
| Battery flow reversal | The flow direction is reversed, for example during charging, to reduce temperature gradients across cells |
The patent also says that battery warming can be used for preconditioning before charging, or when cold conditions reduce range.
What we confirmed in the patents
We checked Google Patents. It notes that the status display is "an assumption, not a legal conclusion."
| Number | Title | Dates | Status |
|---|---|---|---|
| US10967702B2 (publication US20190070924A1) | Optimal source electric vehicle heat pump with extreme temperature heating capability and efficient thermal preconditioning | Priority September 7, 2017; granted April 6, 2021 | Active |
| US11932078B2 | Electric vehicle heat pump using enhanced valve unit | Priority March 31, 2021; granted March 19, 2024 | Active |
| US12365215B2 (a continuation of the one above) | Same | Granted July 22, 2025 | Active |
- The applicant of all three is Tesla Inc.
- The word "octovalve" is defined in US11932078B2 and US12365215B2.
- The older US10967702B2 writes "8-way valve," and in the part we could read, the word "octovalve" did not appear. We could read only part of it, though.
In real cars: a 2020 teardown report
A report (Jalopnik, May 8, 2020, by David Tracy) introduces the Octovalve from a Model Y teardown by the benchmarking firm Munro & Associates. According to it:
- The valve sits in a recess in a nylon coolant manifold (a part that gathers flow paths).
- It is driven by an electric stepper motor with four positions.
- It sends coolant to the motors, the battery, power electronics and more.
- Two electric water pumps sit next to it.
But this is a third party's teardown report. It is not an explanation of the car's structure in official Tesla materials.
What we could not confirm
- Whether Tesla's official materials (owner's manuals, service documents, the official blog) explain the name or structure of the Octovalve.
- Adoption in other models such as the Model 3 and Cybertruck (we could not confirm it in official materials).
- Official figures for how much the Octovalve improved efficiency or range.
- Which modes in the patents are used in real cars, and how often.
From how the patents are written, we can read the aim of "reusing heat by re-connecting the loops of the battery, drive units, radiator and so on with a single valve." But a patent is a document saying "we thought of this mechanism." How real cars behave is a separate matter.
FAQ
What is the Octovalve?
A coolant switching valve that Tesla's patent defines as a valve with eight ports. Rotating the stemshell changes which ports are connected.
What does the Octovalve connect?
In the patent's description: the battery, the drive units, the liquid-cooled condenser, the radiator, the chiller and more.
Does the Octovalve improve winter range?
The patent describes uses such as warming the battery, but we could not confirm an official figure for how much range improves.
Which cars use it?
There is a teardown report on the 2020 Model Y (Jalopnik). We could not confirm other models in official materials.
Summary
- The Octovalve is a coolant switching valve that patent US11932078B2 (granted March 19, 2024) defines as "a valve with eight ports."
- It re-connects the battery, drive units, LCC, radiator, chiller and more in series, in parallel and so on (the patent's description).
- A 2020 teardown report describes a valve driven by a four-position stepper motor in the Model Y. But it is a third party's report.
- Explanations in official Tesla materials, adoption in other models, and efficiency figures are unconfirmed.
Next: we will look, in order, at the motor and inverter that turn electric power into motion (coming soon).
Sources (checked 2026-10-15)
- U.S. Patent US11932078B2, "Electric vehicle heat pump using enhanced valve unit" (Tesla Inc, March 19, 2024): https://patents.google.com/patent/US11932078B2/en
- U.S. Patent US12365215B2 (continuation of the above, July 22, 2025): https://patents.google.com/patent/US12365215B2/en
- U.S. Patent US10967702B2 (publication US20190070924A1, Tesla Inc, April 6, 2021): https://patents.google.com/patent/US20190070924A1/en
- Jalopnik (May 8, 2020, David Tracy), "The Tesla Model Y's Octovalve And Cooling System Manifolds Are Simply Amazing": https://jalopnik.com/the-tesla-model-ys-octovalve-and-cooling-system-manifol-1843342722
This article is for learning about science and technology, and is not investment advice. Facts and the author's interpretation are kept separate. Figures are AI-generated illustrations.