Experience, Reliability and Quality all Important elements with Connectors for Battery Management Systems

The ideal connector solution offering all the performance required by automotive applications

Background

The development division of the car manufacturer, the subject of this case study, was deciding which connectors to use on the battery management system (BMS) to be fitted to a new electric vehicle model it was developing. In the past, the connector selection process had been led by the battery manufacturer, but this time it was agreed that the car manufacturer should choose the connectors in the interests of optimizing performance. However, finding connectors of the right size that could deliver the environmental performance the market demanded was a challenge.

Challenges

Optimization Involved More Than Simply Finding Thinner and More Compact Connectors

The role of a BMS is to monitor the battery’s status to ensure it operates safely and efficiently. Demand for these systems, which are used in both electric vehicles and plug in hybrids, is currently growing. However, to minimize the weight penalty associated with additional systems and maintain interior space and comfort, the manufacturer needed to make the BMS lighter and more compact, and therefore needed to make the connectors used to connect the various modules thinner and more compact as well. At the same time, it was imperative that the system met stringent environmental requirements for temperature, humidity, and vibration.

コネクタ　自動車　解決事例

The design engineer from the development team who was charged with selecting the connectors reflects.

“While traditionally the battery manufacturer had been in charge of selecting the connectors, this time it was agreed that we should handle the selection process to ensure optimum performance. First, we tested a few compact connectors offered by one of our suppliers, but none of them met our requirements. We anticipated a challenging selection process,” says the design engineer.

コネクタ　自動車　解決事例

Because all the pairs of compact connectors the engineer tested had low mating force, he was concerned about their vibration resistance and ability to avoid discontinuity. In addition to ensuring that the connectors were compact and slim-line, it was also important to make sure that they had high mating force and good terminal retention. The supplier’s lack of experience with the automotive industry was a source of concern as well.

“Because the electric vehicle market is still in its infancy, there are still many outstanding technical issues. This means that when developing equipment, not only quality but reliability and track record in the auto industry are very important,” said the engineer.

Despite having been tasked with choosing the connectors, the engineer simply could not find a set of BMS connectors that satisfied all his client’s requirements. As the number of requirements increased, he was at a loss for what solution to use.

Summary of Challenges

There was a need to make the BMS connectors more compact and slim-line.

It was imperative that the connectors were durable and had a high enough mating force and terminal retention to satisfy stringent environmental requirements.