Method to determine the state of charge and remaining life of lithium batteries used in oilfield services applications
First Claim
1. An oilfield services downhole tool battery having a remaining life indicator comprising:
- a housing containing one or more electrochemical cells having an internal anode means which selectively gets consumed at a predetermined state of discharge thereby creating a step change in the cell'"'"'s output voltage which is greater under ambient temperatures than at downhole temperatures; and
remaining life indicator means for providing an indication of remaining life by detecting the step change in the cell'"'"'s output voltage at ambient temperature upon administering a suitable current load.
0 Assignments
0 Petitions
Accused Products
Abstract
The present invention relates to a new method of constructing and interrogating electrochemical cells, especially those having lithium thionyl chloride (Li/SOCl2) chemistry, that permits rapid estimation of remaining discharge capacity. A preferred embodiment of the present invention employs cells with specially modified anode structures and a method for testing the state of charge and remaining life of these cells, as well as depassivating these cells, prior to their intended use or re-use. The test method can be performed using an inexpensive DC circuit and voltmeter at ambient conditions anytime prior to cell use or re-use. There is also disclosed an oilfield services downhole tool battery having a remaining life indicator comprising a housing containing one or more electrochemical cells having an internal anode means which selectively gets consumed at a predetermined state of discharge thereby creating a step change in the cell output voltage which is imperceptible to the tool while in operation at downhole temperatures, and which is capable of being detected at the surface under ambient temperatures upon administering of a suitable current load enabling the user to determine the remaining battery life at the surface prior to subsequent use or reuse of the battery in downhole oilfield services operations.
53 Citations
22 Claims
-
1. An oilfield services downhole tool battery having a remaining life indicator comprising:
-
a housing containing one or more electrochemical cells having an internal anode means which selectively gets consumed at a predetermined state of discharge thereby creating a step change in the cell'"'"'s output voltage which is greater under ambient temperatures than at downhole temperatures; and remaining life indicator means for providing an indication of remaining life by detecting the step change in the cell'"'"'s output voltage at ambient temperature upon administering a suitable current load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 19, 20, 21)
-
-
17. A method of determining the remaining life in an oilfield services battery prior to or after the use or reuse of said battery for downhole oilfield operations comprising the steps of:
-
a) providing an oilfield services downhole tool battery having a remaining life indicator comprising a housing containing one or more electrochemical cells having an internal anode means which selectively gets consumed at a predetermined state of discharge thereby creating a step change in the cell output voltage which is greater under ambient temperatures than at downhole temperatures and remaining life indicator means capable of detecting the step change in the cell output voltage at ambient temperatures upon administering a suitable current load; b) interrogating said battery at the surface at ambient temperatures prior to use or reuse sufficient to acquire repeatable loaded voltage values; and c) comparing the loaded voltage values with predetermined values of voltage versus capacity for said battery to determine whether said step change in output voltage has occurred indicating that a predetermined state of discharge has elapsed. - View Dependent Claims (18)
-
-
22. An oilfield services downhole tool battery having a remaining life indicator comprising:
-
a housing; an electrochemical cell having an internal anode configured to be selectively consumed at a predetermined state of discharge thereby creating a step change in the cell'"'"'s output voltage which is greater under ambient temperatures than under downhole temperatures; and a remaining life indicator arranged to selectively apply a current load to the cell at ambient temperatures and provide an indication of remaining life by detecting the step change.
-
Specification