Don't ever make bats go where they are unfamiliar in exiting. It can cause back ups and confusion for them which only leads to issues.
Do a watch to help to determine to the best of your ability where they are exiting and prepare a device large enough to allow them to crawl out and fly off as they have been accustomed to doing. Seal off and tighten up the remainder of the ridge vent prior to venting the bats.
And of course you need to seal the remainder of the home.
Here is a method I devised several years back that we have used many times on commercial schools and residential homes for bats using ridge vents as a means of structural entry. These devices have worked well for us and I still keep them on hand as a result.
Some of the devices were rather large but light weight. The size was needed to cover the wide area that the bats were using to exit. I basically created a large funnel that was taped and attached to the ridge cap at the exiting position. In this case it was on a cap tile ridge on this particular roof with a slate roof construction.
They can be used on asphalt shingles or tin roofs also.
I framed the large eviction devices from lathe wood 1" x 3" to make them rigid but light. I then stapled some weed block material to the wood frame to the size and shape that I desired. I left a cloth apron on the back side of the device to allow enough material to fasten it to the roof to prevent any entry under the weed block material in the rear.
Duck tape with some Hercules putty worked very well on a clean roof. The devices held fast long enough to get a good eviction. We then slowly sealed the cap tiles individually. It was slow going sealing individual tiles due to the overlap design. Very tedious work but it can be done.
In the front funnel part is the eviction/exit point which is the narrow end on the down side of the device. I left about 3/8" gap at the bottom of the exit point in the weed block material. It was about 2" across at that point.I worked extremely well.
Here are some photos I found in my library of this job.
Some bat jobs can present challenges due to the construction design of the building. Many times forcing you to make adaptable devices that fit the situation the best to allow a fast and unobstructed exit of the colony.
This job had a large colony that chose for their reasons to use several exit points in the ridge which forced me to make multiple devices to make the exiting system work the best without making the bats look for other exit points.
It is never a good idea to force any animal or bats to search for other exit points then those that they are already familiar with and have been using regularly. That way of thinking leads to problems for the consumer and potential back ups. Ultimately a big head ache for you in many cases.
Another device I make and have used for many years in dormer type areas.