1. Technical Field
The embodiments described herein relate to portable electrical energy storage devices, such as those used to power electric powered devices such as vehicles and consumer electronics, and connectors for making an electrical connection between such portable electrical energy storage devices and devices to be powered by or used to charge such portable electrical energy storage devices.
2. Description of the Related Art
Batteries such as lithium-ion batteries are known for storing more energy into smaller, lighter units. Lithium-ion batteries have found wide application in powering portable electronic devices such as cell phones, tablets, laptops, power tools and other high-current equipment. The low weight and high energy density also makes lithium-ion batteries attractive for use in hybrid electric vehicles and fully electric-powered vehicles.
In some applications, a plurality of individual lithium-ion batteries are packaged together to form a battery pack. Such battery packs include electrical components that make electrical connection between the plurality of individual lithium-ion batteries and primary negative and positive electrical terminals of the battery pack. The negative and positive electrical terminals of the battery pack can be connected to corresponding negative and positive electrical terminals of a device to provide electric power to the device. In applications such as computers or mobile phones, the electric connection to the electrical terminals of the battery pack often can only be achieved when the battery pack is inserted into the battery compartment in one position. In other positions, the battery pack either cannot be received into the battery compartment and/or the terminals of the battery pack do not make electrical connection to the terminals of the device. Similarly, chargers for such types of battery packs often include compartments for receiving the battery pack to be charged. The battery compartment of these chargers is often a replica of the compartment contained in the device to be powered by the battery pack. As with the devices, if the battery pack is not oriented properly in the battery compartment of the battery charger, the battery pack may be not be accepted into the compartment and/or the electrical terminals of the battery pack may not make electrical connection with the electrical terminals of the charger. In other instances, when the battery pack is received into the battery compartment of the charger or device in an improper orientation, the electrical terminals of the battery pack may make contact with the electrical terminals of the charger or the device; however, such contact may not meet the design parameters set for the electrical connection between the battery pack and the charger and/or device. For example, the area of contact between the electrical terminals of the battery pack and the electrical terminals of the device or charger when the battery pack is not in its proper orientation may be less than the area of contact between the electrical terminals of the battery pack and the electrical terminals of the device or charger when the battery pack is in its proper orientation. This reduced area of contact when the battery pack is not in its proper orientation can result in the temperature of the electrical terminals rising to undesired and potentially unsafe levels.
Insertion of a battery pack in an improper orientation within a device to be electrically powered by the battery pack or within a device for charging the battery pack may occur due to the user's lack of understanding the proper orientation or due to carelessness on the part of the user. With the proliferation of electric powered devices, such as electric powered tools, appliances, personal portable communication devices, laptop and tablet computers, personal media devices, vehicles and the like, there is interest in battery pack and battery pack electrical connection designs that minimize the likelihood of installing a battery pack in an orientation within a device to be powered by the battery pack or within a device for charging the battery pack such that the electrical power does not flow between the two or does flow, but creates unsafe conditions. Avoiding improper orientation avoids the risk of creating potentially unsafe conditions and promotes proper discharge and charging of the battery pack, as well as avoiding damage to the terminals of the battery pack and/or terminals of the electrically powered device or charging device.
Connectors capable of electrically connecting a source of electrical energy to a device to be powered by electrical energy from the source of electrical energy without regard to the rotational orientation of the connector are known. For example, connectors historically referred to as 12V cigarette lighter socket, utilize a round female connector and a round male connector. An electrical connection can be made between the two, regardless of the rotational orientation the male connector is inserted in the female connector. Such types of connectors are designed for 12V systems and typically have recommended maximum operating currents on the order of 5 to 10 amps, well below current levels required for modern day high current draw devices, e.g., electric powered tools, electric powered appliances and electric powered vehicles, which draw current at levels one or two orders of magnitude greater than current levels 12V cigarette lighter electrical connectors are rated.
Even when a battery pack is installed/inserted in a proper orientation, the electrical connection between electrical terminals of the battery pack and electrical terminals of a device to be powered by the battery pack or a device for charging the battery pack may not operate as designed. For example, unwanted conductive or nonconductive materials could become lodged between the terminals of the battery pack and the terminals of the device or charger. Portions of the terminals could become damaged or could be broken off. Such conditions can result in unsafe conditions and degraded performance. Thus, even in situations where the battery pack is installed/inserted in its proper orientation, there is interest in effective ways to confirm the electrical connection between the electrical terminals of the battery pack and the electrical terminals of the electrically powered device or the device for charging the battery is as designed.