Passive architectures for batteries having two different chemistries

Patent metadata

Field	Value
Publication number	US-10020485-B2
Application number	US-201715839610-A
Country	US
Kind code	B2
Filing date	Dec 12, 2017
Priority date	Jul 31, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A 12 volt automotive battery system includes a first battery coupled to an electrical system, in which the first battery include a first battery chemistry, and a second battery coupled in parallel with the first battery and selectively coupled to the electrical system via a first switch, in which the second battery includes a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry. The first switch couples the second battery to the electrical system during regenerative braking to enable the second battery to capture a majority of the power generated during regenerative braking. The 12 volt automotive battery system further includes a variable voltage alternator that outputs a first voltage during regenerative braking to charge the second battery and a second voltage otherwise, in which the first voltage is higher than the second voltage.

First claim

The invention claimed is:

1. An automotive vehicle comprising:
a 12 volt battery module, wherein the 12 volt battery module comprises:
a first battery electrically coupled between a positive terminal and a negative terminal of the 12 volt battery module, wherein the first battery comprises a first battery chemistry;
a second battery electrically coupled between the positive terminal and the negative terminal of the 12 volt battery module in parallel with the first battery, wherein the second battery comprises a second battery chemistry that has a higher charge acceptance rate than the first battery chemistry; and

an alternator electrically coupled to the positive terminal and the negative terminal of the 12 volt battery module; and
a control unit communicatively coupled to the alternator, wherein the control unit is programmed to, while the automotive vehicle is accelerating or cruising, micro-cycle the 12 volt battery module by:
instructing the alternator to output electrical power used to charge the 12 volt battery module when a first state of charge of the first battery is depleted to a lower state of charge threshold; and
instructing the alternator to cease outputting electrical power to the 12 volt battery module when the first state of charge of the first battery is charged up to an upper state of charge threshold.

2. The automotive vehicle of claim 1 , wherein the control unit is programmed to:
instruct the alternator to output electrical power with a first voltage during micro-cycling of the 12 volt battery module to enable charging a second state of charge of the second battery up to a first value; and
instruct the alternator to output electrical power with a second voltage greater than the first voltage while the automotive vehicle is decelerating to enable charging the second state of charge of the second battery up to a second value greater than the first value.

3. The automotive vehicle of claim 1 , wherein the control unit is programmed to instruct the alternator to output electrical power with voltage greater than open circuit voltage of the first battery at the upper state of charge threshold while the automotive vehicle is decelerating to facilitate continuing to charge the second battery even after the first battery is charged up to the upper state of charge threshold.

4. The automotive vehicle of claim 1 , wherein the first battery and the second battery are partial voltage matched such that a first voltage range of the first battery and a second voltage range of the second battery partially overlap, wherein:
the first voltage range comprises open circuit voltage of the first battery from 0-100% state of charge;
the second voltage range comprises open circuit voltage of the second battery from 0-100% state of charge; and
a portion of the second voltage range that overlaps with the first voltage range corresponds to between 1-74% of total state of charge range of the second battery.

5. The automotive vehicle of claim 1 , wherein the first battery is configured to be micro-cycled between 95% state of charge and 100% state of charge to facilitate steering electrical power output from the alternator while the automotive vehicle is decelerating to the second battery using internal resistance of the first battery.

6. The automotive vehicle of claim 1 , wherein:
the 12 volt battery module comprises a relay electrically coupled between the second battery and the positive terminal; and
the control unit is programmed to:
determine when a condition expected to cause an overvoltage is present; and
instruct the relay to switch from a connected position to a disconnected position to block charging and discharging of the second battery while the condition is present.

7. The automotive vehicle of claim 1 , wherein:
the first battery comprises a first plurality of battery cells, wherein each of the first plurality of battery cells comprises a lead-acid battery cell; and
the second battery comprises a second plurality of battery cells, where each of the second plurality of battery cells comprises a lithium-titanate anode.

8. The automotive vehicle of claim 1 , wherein the control unit is programmed to:
determine open circuit voltage of the first battery; and
determine the first state of charge of the first battery based at least in part on the open circuit voltage of the first battery.

9. A method for operating a battery module implemented in an automotive vehicle, comprising:
determining, using at least one processor, a first state of charge of a first battery electrically coupled in parallel with a second battery in the battery module, wherein the first battery comprises a first plurality of battery cells that each uses a first battery chemistry with a lower coulombic efficiency than a second battery chemistry used by each of a second plurality battery cells in the second battery;
micro-cycling the battery module by instructing, using the at least one processor, an electrical generator in the automotive vehicle to periodically output first electrical power with a first voltage based at least in part on the first state of charge of the first battery while the automotive vehicle is accelerating or cruising; and
capturing regenerative braking energy by instructing, using the at least on processor, the electrical generator in the automotive vehicle to continuously output second electrical power with a second voltage greater than the first voltage while the automotive vehicle is decelerating to facilitate increasing storage capacity of the battery module used to capture the regenerative braking energy.

10. The method of claim 9 , wherein micro-cycling the battery module comprises:
instructing the electrical generator to output the first electrical power when the first state of charge of the first battery is depleted to a lower state of charge threshold; and
instructing the electrical generator to cease outputting the first electrical power when the first state of charge of the first battery is charged up to an upper state of charge threshold.

11. The method of claim 9 , wherein determining the first state of charge of the first battery comprises:
determining open circuit voltage of the first battery; and
determining the first state of charge of the first battery based at least in part on the open circuit voltage of the first battery.

12. The method of claim 9 , wherein:
micro-cycling the battery module comprises instructing the electrical generator to output the first electrical power such that the first voltage is less than or equal to open circuit voltage of the first battery when the first battery is at 100% state of charge; and
capturing regenerative braking energy comprises instructing the electrical generator to output the first electrical power such that the second voltage is greater than the open circuit voltage of the first battery when the first battery is at 100% state of charge.

13. The method of claim 9 , wherein:
micro-cycling the battery module comprises instructing the electrical generator to output the first electrical power to enable charging a second state of charge of the second battery up to a first value; and
capturing regenerative braking energy comprises instructing the electrical generator to output the second electrical power to enable charging the second state of charge of the second battery up to a second value greater than the first value.

14. The method of claim 9 , comprising:
determining, using the at least one processor, when a condition expected to cause an overvoltage is present; and
instructing, using the at least one processor, a first relay electrically c

Assignees

• Johnson Controls Tech Co

Inventors

• Wyatt Perry M
• Le Daniel B
• Mascarenhas Ryan S
• Sisk Brian C

Classifications

• H01M10/06 Primary

  Lead-acid accumulators (semi-lead accumulators H01M10/20) · CPC title

• H01M50/505

  comprising a single busbar · CPC title

• B60L58/20

  having different nominal voltages · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• B60R16/033

  characterised by the use of electrical cells or batteries (for propulsion puposes B60K1/04; supplying batteries to, or removing batteries from, vehicles B60S5/06; testing of charge state G01R31/36) · CPC title