Battery system bi-stable relay control

An automotive battery system, comprising:

• a first battery configured to be coupled to an electrical system, wherein the first battery comprises a first battery chemistry;
• a second battery coupled in parallel with the first battery, wherein the second battery comprises a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry;
• a bi-stable relay configured to selectively couple the second battery to the electrical system, wherein the bi-stable relay is configured to switch from a closed position to an open position or from an open position to a closed position when an instant of power is received, and wherein the bi-stable relay is configured to:
• electrically connect the second battery to the electrical system during regenerative braking when a vehicle is in a key-on position to enable the second battery to capture a majority of power generated during regenerative braking,
• electrically connect the second battery to a starter of the vehicle when a vehicle transitions from a key-off position to the key-on position and a first voltage of the first battery is less than a second voltage of the second battery to enable the first battery and the second battery to supply power to the starter together;
• electrically disconnect the second battery from the electrical system when the vehicle transitions from the key-off position to the key-on position and the first voltage is greater than the second voltage to enable the first battery to supply power to the starter by itself;
• electrically connect the second battery in parallel with the first battery to the electrical system when the vehicle is in the key-off position and the second voltage is greater than a threshold voltage to enable the first battery and the second battery to supply power to the electrical system together;
• and
• electrically disconnect the second battery from the electrical system when the vehicle is in the key-off position and the second voltage is not greater than the threshold voltage to enable the first battery to supply power to the electrical system by itself.

A 12 volt automotive battery system, comprising:

• a first battery configured to be selectively coupled to an electrical system, wherein the first battery comprises a first battery chemistry;
• and
• a second battery comprising a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry;
• an alternator configured to output a first voltage during regenerative braking and to output a second voltage otherwise, wherein the first voltage is higher than the second voltage and higher than a maximum charging voltage of the first battery;
• and
• one or more bi-stable relays configured to be electrically connected to the electrical system, wherein the bi-stable relay is configured to:
• selectively couple the first battery to the electrical system;
• use power to switch from a closed position to an open position to electrically disconnect the first battery during regenerative braking to enable the second battery to be charged at the first voltage higher than the maximum charging voltage of the first battery;
• electrically connect the second battery to the electrical system in parallel with the first battery when the vehicle is in the key-off position and voltage of the second battery is greater than a threshold voltage to enable the first battery and the second battery to supply power to the electrical system together;
• and electrically disconnect the second battery from the electrical system when the vehicle is in the key-off position and the voltage of the second battery is not greater than the threshold voltage to enable the first battery to supply power to the electrical system by itself.