Temperature compensation for magnetic determination method for the state of charge of a battery

A battery system comprising:

• a battery cell comprising a magnetic material;
• a magnetic property sensor proximate said magnetic material to sense a temperature dependent magnetic property value of said magnetic material, said magnetic property sensor in communication with a controller;
• a temperature sensor proximate said magnetic material to sense a temperature, said temperature sensor in communication with a controller;
• wherein said controller comprises software to determine a temperature compensated magnetic property value from said temperature dependent magnetic property value, and further comprising a second magnetic property sensor proximate a second magnetic material, said second magnetic material the same as said first magnetic material, said second magnetic property sensor in communication with said controller, said second magnetic material in thermal equilibrium with said battery cell, said magnetic response of said second magnetic material providing a reference magnetic property value independent of a state of charge (SOC) of said battery cell to determine said temperature compensated magnetic property value.

A method of determining a state of charge (SOC) of a battery system comprising:

• determining a temperature dependent magnetic property value of a magnetic material proximate a battery cell, said magnetic property value dependent on a state of charge (SOC) of said battery cell;
• determining a temperature of said magnetic material;
• determining a temperature compensated magnetic material value from said temperature dependent magnetic property value;
• and,
• using said temperature compensated magnetic material value as an input to a state of charge (SOC) estimator to determine a state of charge (SOC) of said battery system.

A method of determining a state of charge (SOC) of a battery system comprising:

• determining a temperature dependent magnetic property value of a magnetic material proximate a battery cell, said magnetic property value dependent on a state of charge (SOC) of said battery cell;
• determining a temperature of said magnetic material;
• determining a temperature compensated magnetic material value from said temperature dependent magnetic property value;
• and,
• using said temperature compensated magnetic material value as an input to a state of charge (SOC) estimator to determine a state of charge (SOC) of said battery system, and further comprising determining a temperature dependent reference magnetic property value of a second magnetic material substantially the same as said first magnetic material, wherein said reference magnetic property value is independent of a state of charge (SOC) of said battery cell while being in thermal equilibrium with said battery cell and wherein said temperature dependent reference magnetic property value is used to determine said temperature compensated magnetic property value.

A method of determining a state of charge (SOC) of a battery system comprising:

• determining a temperature dependent magnetic property value of a first magnetic material proximate a battery cell, said temperature dependent magnetic property value dependent on a state of charge (SOC) of said battery cell;
• determining a temperature dependent reference magnetic property value of a second magnetic material, said reference magnetic property value independent of a state of charge (SOC) of said battery cell, said second magnetic material substantially the same as said first magnetic material, said second magnetic material in thermal equilibrium with said battery cell;
• determining a temperature compensated value of said magnetic material;
• and,
• using said temperature compensated value as an input to a state of charge (SOC) estimator to determine a state of charge (SOC) of said battery system.