Tokyo, Japan Wednesday, March 27, 2013 – Mitsubishi Motors Corporation (MMC) reports one instance of a melted area in a part of the drive battery pack of an Outlander PHEV caused by an overheating battery cell. Details are as follows:
1. Description of occurrence
On March 20, 2013, an Outlander PHEV was charged fully from a standard outlet then stored at a dealership in Yokohama. The next day (March 21), the dealer personnel attempted to move the vehicle from storage for delivery to a customer (prior to registration) when it was found that it would not move. In addition a strange odor was detected around the vehicle. Upon checking the underbody of the vehicle, signs of melting were observed on the part of the drive battery pack.
When the battery pack was examined by the supplier, it was found that one of the battery pack's 80 cells had overheated, melting adjacent cells. The 80 cells in the drive battery pack are divided and set into three "blocks" within the drive battery pack. Examination found that only one of the three blocks sustained any damage.
No damage to the dealership facilities nor injuries occurred. Outside of the drive battery pack itself, there was no damage to the vehicle.
3. Investigation into Cause
The battery in question was moved to the battery supplier for prompt joint investigation with the supplier into the cause. Although the cause has yet to be fully determined, a possibility includes a defect in the manufacturing process of the battery supplier, resulting in defects in the batteries. MMC is moving forward with continued investigations to determine fully the root cause.
This incident of melting in a drive battery pack happened before the vehicle was registered (and therefore drivable on the road). As of March 21, no cases of drive battery packs melting nor catching fire have ever occurred.
4. To all Mitsubishi Motors Customers
This incident occurred after the battery was fully charged for the first time. Mitsubishi Motors is decisively pushing forward with investigations into the root cause. Based on the above information Mitsubishi Motors suggests that Outlander PHEV drivers refrain from using external charging or Charge Mode until the cause is found. In addition, dealers will be contacting Outlander PHEV customers regarding use of their vehicle as well as responding to customer inquiries.