Heat insulating sheet for heat insulation between battery cells for electric vehicle

A heat insulating sheet for heat insulation between battery cells of an electric vehicle, the sheet comprising:

• a silica aerogel;
• fibers;
• and
• infrared ray shielding particles, wherein
• in a photograph obtained by observing a cross section of the sheet, first particles composed of the infrared ray shielding particles each having a major axis length of 0.5 μm or more and 1 μm or less and second particles composed of the infrared ray shielding particles each having a major axis length of 5 μm or more and 10 μm or less are present,
• a ratio of a number of the first particles to a number of the second particles each present in the photograph is first particles:second particles=1:4 to 3:1, and
• in the photograph, a sum of a percentage of the number of the first particles and a percentage of the number of the second particles in the infrared ray shielding particles each having a major axis length of 0.5 μm or more and 10 μm or less is 20% or more and 30% or less.