The following questions are commonly asked about Cymbet EnerChip Rechargeable Energy Storage Devices.

If the answer provided below is not answered satisfactorily, please contact Cymbet directly using the Support Form.

Q1: May I use a constant current source to charge the battery?

A: Yes, however it must be followed by a constant voltage mode and in both modes the voltage must not exceed the recommended charging voltage.  See AN-1002 for recommended charge circuits and charging guidelines.

Q2: Can I use a standard Li-ion battery charger?

A: Yes; however, the battery charging current will be very low and the reverse leakage current must be kept low in order to prevent the battery from discharging through the charge circuit.

Q3: How will I know when the rechargeable battery is fully charged?

A: Either by time or current. The rechargeable battery are typically fully charged in about one hour; as the battery becomes fully charged, the current will decay to less than about 250 nA for the CBC012 and less than about 1 µA for the CBC050.

Q4: What happens if I charge the rechargeable battery before it has been soldered to a board?

A: The battery performance will be degraded and, if soldered while in a partially or fully charged state, might be destroyed.  See AN-1001 .

Q5: What if I short-circuit the rechargeable battery or discharge it to zero volts slowly?

A: The battery cycle life will be reduced from its rated value. See AN-1002 .

Q6: What happens if I apply a voltage higher than the recommended charging voltage to the rechargeable battery?

A: The battery will likely be destroyed.

Q7: Do I need to use a safety circuit to prevent overheating or short-circuiting of the rechargeable battery?

A: No; however, discharging the battery to less than 3V will affect the cycle life of the battery.  See AN-1002 .

Q8: What happens if the cell is short-circuited? Will it explode or leak harmful chemicals?

A: No. There are no harmful chemicals to leak and the battery will not explode.

Q9: Do I need to use a constant current followed by constant voltage charger?

A: No, although that charge method is permissible. A constant voltage charge method is acceptable. See AN-1002 .

Q10: What types of protection circuits are required?

A: It is necessary to limit the battery charge voltage to no more than the recommended charge voltage. It is also important that external power supplies are not connected to the battery terminals except in accordance with Cymbet’s battery charging guidelines. See AN-1002.

Q11: What is the temperature range of the cell?

A: The operating temperature range can be found in the data sheets for each product; the data sheets can be found here: Contact

Q12: What cell capacities are available?

A: Please see the product data sheets at: Products

Q13: How many charge discharge cycles can the cell do?

A: See the product data sheets at: Products

Q14: How long will the cell hold a charge?

A: The self-discharge of the cell is a function of several parameters, including temperature. For the self-discharge specifications, see the product data sheets: Products

Q15: What happens if the cell is left in a discharged state for a long period of time?

A: Leaving the cell in a discharged state is not detrimental to the cell performance.

Q16: What happens if the cell is charged indefinitely?

A: Charging the cell indefinitely is not harmful to it.

Q17: What is the cell impedance?

A: The cell impedance is determined by a number of factors, including the surface area of the cell. For specific specifications of cell impedance, see the product data sheets at: Products

Q18: Can the cell be solder reflowed? Lead free?

A: Yes, the cells are tolerant to the lead-free 260°C reflow soldering profile.

Q19: What is the nominal voltage of the cell?

A: The nominal output voltage of the cell is 3.8V; at approximately 3.0V, the charge on the cell is nearly fully depleted at low discharge currents. See the product data sheets at products page for typical discharge profiles.

Q20: What is the pulse current capability of the cell?

A: See the product data sheets at Products

Q21: Are the Cymbet rechargeable batteries sensitive to electrostatic discharge (ESD)?

A: Yes. Prior to charging the batteries, they are sensitive to ESD and should be handled accordingly. See AN-1001.

Q22: What are the weights of the EnerChip Devices?

A: The weights of the EnerChip Devices are as follows:

  • Packaged EnerChips
  • CBC3150-D9C is 0.22 g
  • CBC050-M8C is 0.19 g
  • CBC3112-D7C is 0 .14 g
  • CBC012-D5C is 0 .068 g

Bare dies

  • CBC050-BDC is 0.016 g
  • CBC012-BDC 0.005 g
Q23: What Energy Harvesting transducers are recommended for the EVAL-09?

A: Other types of EH transducers include: Thermoelectric Generators (TEGs) – There are several vendors of thermoelectric generators. MicroPelt model MPG-D651 or MPG-D671 have been verified with the CBC-EVAL-09. MicroPelt’s evaluation system is TE-Power PLUS, described on www.micropelt.com and available at Mouser. Nextreme also supplies a small TEG, model eTEG HV56 Power Generator. Contact Nextreme directly at www.nextreme.com.

Piezo Electric Generator – There are several vendors of piezoelectric generators. Mide piezo units V20W, V25W, V21B, V21BL, V22B, and V22BL have been verified with the CBC-EVAL-09. Mide’s website is www.mide.com. Another vendor is Advanced Cerametrics (ACI). Model numbers PFCB-W14, PFCB-W24, and PFCB-W54 will work with the EVAL-09. ACI’s website is www.advancedcerametrics.com.

Alternate Energy Harvesting Generators – New solutions for harvesting ambient energy are emerging from companies and universities worldwide. Please contact Cymbet Applications Engineering to discuss your requirements.

For other details using various EH transducers with the EVAL-09 Universal Energy Harvesting Kit view the EVAL-09 datasheet.

Getting Started

We look forward to accelerating your new design projects by leveraging the advantages of Cymbet EnerChip rechargeable solid state batteries, power management and integrated solutions.

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