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Primary-secondary hybrid battery

  • US 4,851,756 A
  • Filed: 01/08/1987
  • Issued: 07/25/1989
  • Est. Priority Date: 01/08/1987
  • Status: Expired due to Fees
First Claim
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1. A hybrid battery which provides backup energy for at least one main power source connected to a load, comprising:

  • a. a rechargeable first battery,b. a second battery,b. means for selectively connecting the at least one main power source, the rechargeable first battery, and the second battery to the connected load based on which energy source has the highest voltage available, said means for selectively connecting comprising at least one solid state switch which connects the rechargeable first battery to the connected load upon the loss of the at least one main power source, gradually connects the second battery to the connected load through load sharing with the rechargeable first battery upon the discharge of the rechargeable first battery below a predetermined voltage level, disconnects the rechargeable first battery upon the return of the at least one main power source, and disconnects the second battery upon the charging of the rechargeable first battery above the predetermined voltage level, said switch isolating the energy sources from one another; and

    d. means for compensating for the forward-voltage drop of the at least one solid state switch.

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