Wireless communications, including radio frequency identification (RFID) and other near field communication (NFC) protocols, are gaining in popularity for applications such as security, inventory management, access control, and the like. The number of smartphones and mobile devices that include RFID or NFC protocols is growing along with the various applications of passive or active transponders, such as RFID circuits and NFC circuits. Such communications circuits may be coupled with an antenna that modulates, and in some instances emits, a wireless communication signal that can be read by a reader, such as a smartphone.
Electrochemical cells, or batteries, are commonly used as electrical energy sources. A battery contains a negative electrode and a positive electrode. The negative electrode contains an active material that can be oxidized. The positive electrode contains an active material that can be reduced. The negative active material is capable of reducing the positive active material. A separator is disposed between the negative electrode and the positive electrode. An electrolyte is also included within the battery. The aforementioned components are generally disposed in a housing, such as a metal can with an open end, that is crimped over an end cap and seal to close the battery. The battery may be primary, i.e., meant to be discharged to exhaustion one time and then discarded. The battery may, alternatively, be secondary, i.e., meant to be discharged and recharged multiple times.
Battery testers may be used to determine characteristics of the battery, such as the remaining battery capacity. An exemplary type of a common battery tester is known as a thermochromic tester. In a thermochromic tester, a circuit may be completed when a consumer manually depresses a one or two button switch. Once the switch is depressed, the consumer has connected the battery to the thermochromic tester. The thermochromic tester may include a silver resistor, e.g., a flat silver layer that has a variable width so that the electrical resistance also varies along its length. As current travels through the silver resistor, the dissipated power generates heat that changes the color of a thermochromic ink display that is placed over the silver resistor. The thermochromic ink display may be arranged as a gauge to indicate the relative capacity of the battery. However, it is typically necessary for the consumer to inconveniently hold the battery and/or remove the battery from the device in order to test the battery using the battery tester, such as the thermochromic tester. In addition, in may be difficult to accurately connect the battery tester to the battery.
Accordingly, there exists a need for a battery including an on-cell indicator that does not require manual interaction between the consumer and the battery and/or indicator. In addition, the battery including an on-cell indicator may also include advanced processing and communication capabilities. There also exists a need for a battery including an indicator circuit that does not detrimentally affect the external dimensions of the battery. A need exists to provide an on-cell indicator that easily connects to the battery. There also exists a need to provide a battery with an on-cell indicator that does not have a reduced battery capacity due to the inclusion of on-cell indicator components within the battery housing.