Does this model have a battery backup?

SOURCE: i changed the battery in my smoke alarm and it is

Use a quality battery duracell or energizer. Not ones from the dollar store.

Chirping means low battery.

SOURCE: kidde smoke alarm won't stop chirping

Most smoke detecotrs have a limited lifespan of 5-10 years. On the underside of the detectors should be a sticker with installed dated or replace by date. If changing the batteries doesn't stop the chirping it is most like time to replace the detector. If you check the manufacturer website they will give you a life expectancy for your detector.

SOURCE: Replaced 9 v batteries, units still chirping

This is the troubleshooting information from the kddie site. The problem is usually related to an older battery or improperly installed battery. You might also have to do a reset as described below. If battery and cleaning don't work, it might be time for a replacement - short money to keep you and your home safe.

1. The battery may be loose, or improperly installed.
   Verify that a battery of the recommended type is securely installed. Make sure to use a battery with a use-by date no later than four to five years in the future. Check that the battery is snapped in completely so it cannot be shaken loose. It’s possible that battery connections may not be making good contact with the battery. Disconnecting and re-connecting the battery once or twice will likely fix this condition. On units with a front-load battery, be sure that the battery compartment door is closed completely as well. Loose white neutral wire can cause an echoing chirp. (From one unit to the next)
   
   
2. The smoke alarm sensing chamber may be dirty.
   Dust and insects can collect in the sensing chamber of the alarm. An accumulation of dust in the sensing chamber can cause the unit to chirp. It is good practice to clean the smoke alarm when you change the battery. Static electricity from the ac quick connector attracts dust and can cause false alarms.
   
   Cleaning smoke alarms:
   To clean your alarm, remove it from the mounting bracket as outlined here. You can clean the interior of your alarm (sensing chamber) by using compressed air or a vacuum cleaner hose and blowing or vacuuming through the openings around the perimeter of the alarm. The outside of the alarm can be wiped with a damp cloth. After cleaning, reinstall your alarm, verify the green LED is on and test your alarm by using the Test Button. If cleaning does not restore the alarm to normal operation, the alarm should be replaced.
   
   
3. Check environmental conditions:
   
   • Humidity, steam and condensation can cause false alarms. Causes of condensation are:
     • Extreme temperatures changes.
     • High ambient humidity.
     • Unit being installed in an uninsulated electrical box mounted on a ceiling beneath an attic. If this condition exists you’ll want to move the alarm. Click here to see the correct alarm placement in your user’s manual found in our Download Center.
   • Check to see if there is a cooling/heating register, a ceiling fan or an open window within 3 feet of the alarm. If there is, move the alarm away from the source of the increased airflow. Click here to see the correct alarm placement in your user’s manual found in our Download Center.
   • Check the temperature of the room. Smoke alarms operate at 40 degrees to 95 degrees Fahrenheit. Carbon monoxide alarms operate at 40 degrees to 100 degrees Fahrenheit.
     
     
4. Reset the alarm.
   Some current model smoke alarms have a processor that retains certain error conditions, such as a weak battery. The error condition should reset when the battery is replaced but sometimes it does not and must be manually reset to clear the error.
   
   To reset an AC unit with a battery backup:
   Turn off the power to the smoke alarm at the circuit breaker.Remove the smoke alarm from the mounting bracket and disconnect the power. Remove the battery. Press and hold the test button for at least 15 seconds. The unit may chirp or alarm for a few seconds before going silent.Reconnect the power and reinstall the battery. The unit will chirp once when the power is restored and should not chirp afterwards.
   
   To reset a DC only unit:
   Remove the battery. Press and hold the test button for at least 15 seconds. The unit may chirp or alarm for a few seconds before going silent.Reinstall the battery. The unit will chirp when the battery is first connected but should not chirp afterwards.
   
   
5. An electrical condition may be causing the power to the unit to be interrupted.
   If the AC power to the unit is interrupted, the unit will chirp when the power is restored. This could be caused by power surges. If the chirping seems to occur at about the same time in the evening or morning, it could be due to a surge created when the power company switches electrical grids to meet demand. Check to see if the chirp (or chirping) occurs when something else in the house is turned on such as an exhaust or attic fan, a heater, etc. If the smoke alarm is connected to a circuit with such a device, the alarm may chirp when the other device is switched on. If this is the case and the device is plugged into a wall outlet, move it to another outlet on a different circuit. If it is a hardwired device, have an electrician investigate it. These conditions can be minimized by installing your alarms on a dedicated circuit in compliance with NFPA requirements.
   
   
6. Replace the alarm.
   If none of these conditions exist and the suggestions don't alleviate the symptom, the alarm should be replaced. Age may be a factor. Smoke and heat alarms should be replaced every 10 years, and carbon monoxide and combination alarms should be replaced every 7 years. Most of our alarms have a 5 year warranty from date of purchase (check your user manual for details). A date code is stamped on the label attached to the back of the unit.
   
   

SOURCE: Our smoke alarm with battery

You didn't mention if you had replaced the battery, yet. If you haven't, then that's more than likely the problem. Also, it probably needs cleaning. You can accomplish this by using canned compressed air (like you clean your computer with). Use the straw nozzle to reach all the nooks and crannies. Clean after removing the old battery and before installing the new battery. Batteries should be changed annually and at the same time clean the unit. When using the canned compressed air, try to keep the can in the upright position, as much as possible.