Below is from Air Canada:

Lithium metal or lithium ion cells and batteries

Portable electronic devices with lithium metal or lithium ion cells or batteries, such as watches, calculating machines, cameras, cellular phones, laptop computers*, camcorders, etc., are accepted under the following conditions:

• Lithium metal or alloy cells and batteries:
  • Only lithium metal cells or batteries with a maximum lithium content of 2 grams are allowed.
  • The following are allowed in carry-on baggage only*:
    • Consumer electronic devices containing accepted lithium metal cells or batteries;
    • Spare lithium metal cells or batteries (in reasonable quantities).
  • Batteries must be individually protected to prevent short circuits, e.g. exposed terminals can be taped over, each individual battery can be in a protective pouch or separate plastic bag, or batteries can be in their original retail packaging.

• Lithium ion cells and batteries up to 100 Watt Hours (Wh) each
  • The following are allowed in carry-on baggage only*:
    • Consumer electronic devices containing accepted lithium ion cells or batteries with a rating of not more than 100 Wh each;
    • Spare lithium ion cells or batteries with a rating of not more than 100 Wh each.

• Lithium ion batteries with a rating of 100 but not exceeding 160 Watt Hours (Wh)
  • A maximum of two (2) individually protected spare lithium ion batteries with a rating of 100 Wh but not exceeding 160 Wh may be carried per passenger in carry-on baggage only*, pending approval by Air Canada airport agents.

Alkali-manganese (alkaline), Zinc-carbon (dry cell), nickel metal hydride (NiMH), nickel cadmium (NiCd) and silver oxide batteries (Non lithium)

• Such batteries are allowed in carry-on baggage only*.
• Batteries must be individually protected to prevent short circuits, e.g. exposed terminals can be taped over, each individual battery can be in a protective pouch or separate plastic bag, or batteries can be in their original retail packaging.

Batteries used to power portable battery-powered medical devices

• Batteries used to power portable battery-powered medical devices (e.g. a Personal Oxygen Concentrator (POC), Continuous Positive Airway Pressure (CPAP), Nebulizer) may be carried onboard to power these medical devices, but are subject to prior approval for transport by the Air Canada Medical Assistance Desk.

Batteries used to power mobility aids

• Spillable and non-spillable batteries for battery-powered mobility aids (e.g. wheelchairs) are accepted in checked baggage, but require special handling. See our wheelchair and mobility aid page for more information.

* On smaller aircraft (e.g. Jazz Dash-8 or CRJ) with limited onboard storage space, you’re asked to deposit your carry-on items on a cart as you board the plane. Battery-powered devices and spare batteries must always be removed from carry-on baggage that is deposited on such carts and carried into the aircraft cabin.