Dual Lithium-Ion Battery System for Electric Vehicles

• US 20140265554A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Abandoned Application

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yang, Xiao Guang, Arsenault, Renata Michaela, Anderson, Richard Dyche
• Application Number:
  US13/829,148
• Publication Number:
  US 20140265554A1
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/51 Photovoltaic means
• CPC Class Codes: B60L 53/52 Wind-driven generators
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/20 : having different nominal voltages
• CPC Class Codes: B60L 58/22 : Balancing the charge of battery modules
• CPC Class Codes: B60L 58/26 : by cooling
• CPC Class Codes: B60L 7/12 : for vehicles propelled by dc motors
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A battery system for powering a vehicle is provided. The system may include a first lithium-ion battery pack having a first total energy capacity and a first power to energy ratio (P/E ratio) and a second lithium-ion battery pack connected in parallel with the first lithium-ion battery pack and having a second total energy capacity that is higher than the first total energy capacity and a second P/E ratio that is lower than the first P/E ratio. A method of controlling the battery system is also provided, and may include controlling an operation of a vehicle according to a total power capability of the first and second battery strings, wherein the total power capability is the sum of a first battery string power capability and a second battery string power capability at a same voltage.

Claims

1. A battery system for powering a vehicle, comprising:

a first lithium-ion battery pack having a first total energy capacity and a first power to energy ratio (P/E ratio);

a second lithium-ion battery pack connected in parallel with the first lithium-ion battery pack and having a second total energy capacity that is higher than the first total energy capacity and a second P/E ratio that is lower than the first P/E ratio; and

at least one controller programmed to control the first and second lithium-ion battery packs.

2. The battery system of claim 1, wherein the first P/E ratio is at least 15 kW/kWh and the second P/E ratio is no more than 10 kW/kWh.

3. The battery system of claim 1, wherein the at least one controller is programmed to provide more than half of an electric transient power demand of the vehicle from the first lithium-ion battery pack.

4. The battery system of claim 1, wherein the second lithium-ion battery pack has a total energy capacity of at least 20 kWh.

5. The battery system of claim 1, wherein the second lithium-ion battery pack has a specific energy density of at least 175 Wh/kg.

6. The battery system of claim 1, wherein the first lithium-ion battery pack has a type of positive electrode selected from the group consisting of lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium manganese spinel oxide (Mn Spinel), lithium iron phosphate (LFP), lithium mixed metal phosphate (LFMP), and mixtures thereof and the second lithium-ion battery pack has a positive electrode selected from the group consisting of NCA, NMC, MN Spinel, layered-layered, LFP, LMFP, and mixtures thereof.

7. The battery system of claim 1, wherein the first lithium-ion battery pack has a type of negative electrode selected from the group consisting of graphite, hard carbon, soft carbon, and lithium titanate oxide (LTO) and the second lithium-ion battery pack has a negative electrode selected from the group consisting of graphite, hard carbon, soft carbon, Si-enriched graphite, and Sn-enriched graphite.

8. The battery system of claim 6, wherein the first lithium-ion battery pack and the second lithium-ion battery pack have the same type of positive electrodes.

9. The battery system of claim 6, wherein the first lithium-ion battery pack and the second lithium-ion battery pack have different types of positive electrodes.

10. The battery system of claim 7, wherein the first lithium-ion battery pack and the second lithium-ion battery pack have different types of negative electrodes.

11. A method for operating a vehicle, comprising:

receiving in a vehicle controller information corresponding to limiting voltages of a first and a second lithium-ion battery string, each battery string having different total energy capacity; and

controlling an operation of the vehicle according to a total power capability of the first and second battery strings;

wherein the total power capability is the sum of a first battery string power capability and a second battery string power capability at a same voltage.

12. The method of claim 11, wherein the operation is a discharge of the first and second battery strings and the same voltage is a voltage corresponding to a higher of a minimum voltage of the first battery string and a minimum voltage of the second battery string.

13. The method of claim 11, wherein the operation is a charge of the first and second battery strings and the same voltage is a voltage corresponding to a lower of a maximum voltage of the first battery string and a maximum voltage of the second battery string.

14. The method of claim 11, wherein the first battery string and the second battery string operate over different state of charge (SOC) ranges.

15. The method of claim 11, wherein a SOC is communicated to a vehicle display based on a SOC of the battery string having a higher total energy capacity.

16. The method of claim 11 further comprising controlling operation of the vehicle such that over half of an electric transient power demand of the vehicle is provided by the battery string having a lower total energy capacity.

17. The method of claim 11 further comprising controlling operation of the vehicle such that over half of instantaneous energy generated during braking is received by the battery string having a lower total energy capacity.

18. The method of claim 11 further comprising controlling operation of the vehicle such that if one battery string fails it is taken offline and the other battery string provides substantially all propulsive battery power to the vehicle.