What is the battery model for the BMW 3 Series car key?

[LaBenjamin]

The battery model is CR2032. It is a lithium manganese dioxide battery, named according to the IEC standard. The details are as follows: C- indicates a chemical battery system with lithium metal as the negative electrode and manganese dioxide as the positive electrode; R- indicates the battery shape is cylindrical, with F used for square shapes; 20 indicates the battery diameter is 20mm; 32 indicates the battery height is 3.2mm. The nominal voltage is 3.0V, the endpoint voltage is 2.0V, and the rated capacity is approximately 200mAh. CR2032 typically has a lifespan of 5 years. If the manufacturer's production level is low or quality control is poor, the lifespan can be significantly shortened. Domestic first-tier brand batteries can generally guarantee this lifespan. Under ideal conditions (sealed, room temperature, no moisture, etc.), the lifespan can extend to 8 years or even 10 years. The usage time of the car remote key battery is closely related to the frequency of use—the more frequently it is used, the shorter the battery life. If the remote key battery runs out, the mechanical key can be used to open and start the vehicle. Car remote keys use button batteries, mainly three types: CR2016, CR2025, and CR2032. For the specific model used in each vehicle, owners can refer to the battery model in the user manual for replacement. Button-type CR2016 battery: This is one of the most commonly used car remote batteries. The battery voltage is 3V, and most car key batteries are powered by 9V, so all three batteries need to be replaced each time. Examples include Honda, Toyota, Volkswagen, Mazda, etc. CR2016 specifications: battery diameter 20mm, thickness 1.6mm. Button-type CR2025 battery: Its usage rate is much lower than CR2016, but it is still used in some car keys. It is thicker than CR2016 but has a relatively higher storage capacity. CR2025 specifications: battery diameter 20mm, thickness 2.5mm. This type of battery is also commonly used in audio remotes. Button battery CR2032: It is twice as thick as CR2016. The 3V-CR2032 lithium manganese battery has a lithium-manganese dioxide structure. The positive electrode material is chemically stable manganese dioxide, the negative electrode is lithium metal, and the electrolyte is a lithium battery electrolyte. The main components of the electrolyte are dimethoxyethane, propylene carbonate, and lithium perchlorate. Its shape resembles a button, hence the name button lithium battery or lithium manganese button battery.