Method and apparatus for determining battery capacity in a defibrillator

Abstract

A defibrillator system and associated methodology for determining capacity of a battery and/or a number of battery cells contained in a pack. The system measures and stores the battery or battery pack voltage signal data and uses an algorithm to determine the remaining capacity. The algorithm takes into account the operating mode of the device, historical information of the device including, but not limited to, how long it has been since the device has been used, how the device has been used (e.g. shocking mode or idle mode), how many times the device has been used with its installed battery or battery pack, how many charging cycles and/or shocks have been delivered etc. The output from the system is fed back to the user to inform the user when the battery is low, needs to be replaced and/or how many remaining shocks are left the battery.

1 . A method for determining the remaining battery capacity of a battery in a defibrillator, the method comprising:
 applying an algorithm that calculates remaining battery capacity of a battery using measured battery voltage value in conjunction with historical information previously stored in the defibrillator.   
     
     
         2 . The method according to  claim 1  wherein the algorithm uses a predetermined voltage value threshold for defibrillator in idle mode and at least one other threshold when the defibrillator is charging to deliver at least one shock. 
     
     
         3 . The method according to  claim 1  wherein the algorithm uses the battery voltage value and time period of how long the device has not been used. 
     
     
         4 . The method according to  claim 1  wherein the algorithm uses the battery voltage value and the number of times the device has been used with its installed battery. 
     
     
         5 . The method of  claim 1  wherein the algorithm uses the battery voltage and how many times the device has been used to charge its internal capacitors with its installed battery to determine the remaining capacity of the battery. 
     
     
         6 . The method of  claim 1  wherein the algorithm uses the battery voltage and how many times the device has been used to deliver a biphasic shock to a patient with its installed battery. 
     
     
         7 . The method of  claim 1  wherein the algorithm uses the battery voltage and how long the device has been used to monitor a patient with its installed battery. 
     
     
         8 . The method of  claim 1  wherein the algorithm uses the data to determine the remaining capacity of the battery and informs the user that the battery is low. 
     
     
         9 . The method of  claim 1  wherein the algorithm uses the data to determine the remaining capacity of the battery and informs the user that the battery needs to be replaced. 
     
     
         10 . The method of  claim 1  wherein the algorithm uses the data to determine the remaining capacity of the battery or battery pack and informs the user of the number of shocks left. 
     
     
         11 . The method of  claim 1  wherein the algorithm uses the data to determine the remaining capacity of the battery or battery pack and informs the user of the remaining monitor time. 
     
     
         12 . The method of  claim 1  wherein the algorithm uses the data to determine the remaining capacity of the battery or battery pack and informs the user of the general battery capacity as it relates to typical use. 
     
     
         13 . A defibrillator comprising:
 at least one battery;   at least one capacitor;   a circuit to charge the at least one capacitor from at least one battery;   a circuit to deliver a biphasic waveform from at least one capacitor to the patient;   user notification apparatus for notifying the user of events during defibrillator operation; and   a data acquisition circuit that measures the terminal voltage of the at least one battery, digitizes the signal and stores the data in memory for analysis.   
     
     
         14 . A defibrillator according to  claim 13  wherein at least one battery comprises at least one cell, and further wherein the supply voltage is at least 3V. 
     
     
         15 . A defibrillator according to  claim 13  further comprising at least one Lithium Manganese Dioxide type cell. 
     
     
         16 . A defibrillator according to  claim 13  wherein the data acquisition circuit comprises:
 a microprocessor for executing instructions to sample data, store the data into memory and process the data to determine the remaining battery capacity; 
 a programmable logic device; and 
 an analog-to-digital converter. 
 
     
     
         17 . A defibrillator according to  claim 16  wherein the programmable logic device is configured to (i) control the interface to the analog-to-digital converter, (ii) store the sampled data into a local memory buffer, and (iii) interrupt the microprocessor to sample the data contained in the buffer. 
     
     
         18 . A defibrillator according to  claim 16  wherein the microprocessor directly interfaces with the analog-to-digital converter and uses internal timing to interrupt the microprocessor for sampling the data. 
     
     
         19 . A defibrillator according to  claim 16  wherein the microprocessor comprises a microcontroller with memory, an analog-to-digital converter and other peripherals on a single chip. 
     
     
         20 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to sample battery voltage value and store the data into memory. 
     
     
         21 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to sample battery voltage value and store it onto a removable multi-media flash card for post incident review. 
     
     
         22 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to sample battery voltage value and store it into EEPROM or Flash. 
     
     
         23 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal voltage value and its associated operational mode in memory. 
     
     
         24 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal or voltage value and how long it has been since the device was last used. 
     
     
         25 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal voltage value and how many times the device has been used with its installed battery. 
     
     
         26 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal voltage value and how many times the device has been used to charge its internal capacitors with its installed battery. 
     
     
         27 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal voltage value and how many times the device has been used to deliver a biphasic shock to a patient with its installed battery. 
     
     
         28 . A defibrillator according to  claim 13  wherein the data acquisition circuit is configured to store the measured battery terminal voltage value and how long the device has been used to monitor a patient with its installed battery. 
     
     
         29 . A defibrillator according to  claim 23  wherein the data is stored into random access memory. 
     
     
         30 . A defibrillator system according to  claim 23  where in the data is stored onto a removable multi-media flash card, EEPROM and or Flash. 
     
     
         31 . A method for determining battery capacity in a defibrillator comprising:
 recording historical data comprising at least one from the group consisting of:
 how long it has been since the battery was last charged; 
 how the defibrillator has been used since the battery was last charged, including a record of when the defibrillator was in idle mode and when the defibrillator was in shocking mode; 
 how many shocks have been delivered since the battery was last recharged; 
 how long has it been since the defibrillator was last used in shocking mode; and 
 how many times the battery has been recharged over its lifetime; 
   measuring the current battery voltage; and   applying an algorithm to calculate remaining battery capacity, using the measured battery voltage and the recorded historical data.   
     
     
         32 . A method according to  claim 31 , further comprising notifying the user when the calculated remaining battery capacity is below a selected level. 
     
     
         33 . A method according to  claim 32 , wherein the user is notified if the number of shocks delivered since the battery was last charged exceeds a selected number. 
     
     
         34 . A method according to  claim 32 , wherein the user is notified if the number of shocks delivered since the battery was last charged exceeds a selected number and the current battery voltage is less than a selected voltage. 
     
     
         35 . A method according to  claim 32 , wherein the user is notified if the number of shocks delivered since the battery was last charged is within a selected range and the current battery voltage is less than a selected voltage. 
     
     
         36 . A method according to  claim 32 , wherein the user is notified if the total monitoring time since the battery was last charged is within a selected range and the current battery voltage is less than a selected voltage. 
     
     
         37 . A method according to  claim 32 , wherein the user is notified if the number of shocks delivered since the battery was last charged is below a selected number and the current battery voltage is less than a selected voltage. 
     
     
         38 . A method according to  claim 32 , wherein the user is notified if the total monitoring time since the battery was last charged is below a selected number and the current battery voltage is less than a selected voltage. 
     
     
         39 . A method according to  claim 32 , wherein the user is notified if the time since the battery was last charged exceeds a selected amount. 
     
     
         40 . Apparatus for determining the battery capacity in a defibrillator comprising:
 apparatus for recording historical data comprising at least one from the group consisting of:
 how long it has been since the battery was last charged; 
 how the defibrillator has been used since the battery was last charged, including a record of when the defibrillator was in idle mode and when the defibrillator was in shocking mode; 
 how many shocks have been delivered since the battery was last recharged; 
 how long has it been since the defibrillator was last used in shocking mode; and 
 how many times the battery has been recharged over its lifetime; 
   apparatus for measuring the current battery voltage; and   apparatus for applying an algorithm to calculate remaining battery capacity, using the measured battery voltage and the recorded historical data.