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US-12617313-B2 - Balancing of an electrical energy storage using a low voltage network

US12617313B2US 12617313 B2US12617313 B2US 12617313B2US-12617313-B2

Abstract

Balancing of rechargeable electrical energy storages is described. In particular aspects, the disclosure relates to balancing of an electrical energy storage using a low voltage network.

Inventors

  • Ringolds JARGANS
  • Pavan BALRAM
  • Brajesh Singh

Assignees

  • VOLVO TRUCK CORPORATION

Dates

Publication Date
20260505
Application Date
20231212
Priority Date
20221219

Claims (17)

  1. 1 . A computer system comprising a processor device configured to: detect a charge parameter imbalance between rechargeable electrical energy storage packs of a vehicle, the electrical energy storage packs being independently connectable to a bi-directional DC/DC converter via a traction voltage bus; in response to detecting the imbalance, the processor device is configured to, until each electrical energy storage pack is at a target charge parameter level: (A) connect one or more of the electrical energy storage packs to a bi-directional DC/DC converter connectable to a low voltage electrical energy storage to transfer energy from the one or more electrical energy storage pack to the low voltage electrical energy storage via the bi-directional DC/DC converter, (B) detect that either the low voltage electrical energy storage is at an upper-level capacity or that one of the one or more electrical energy storage pack is discharged to the target charge parameter level, (C) disconnect the one or more electrical energy storage pack from the bi-directional DC/DC converter, (D) connect at least one further electrical energy storage pack to the bi-directional DC/DC converter to transfer energy from the low voltage electrical energy storage to the at least one further electrical energy storage pack via the bi-directional DC/DC converter, (E) detect that either the low voltage electrical energy storage is at lower level capacity or that the one of the at least one further electrical energy storage pack is at the target charge parameter level, and (F) disconnect the at least one further electrical energy storage pack from the bi-directional DC/DC converter.
  2. 2 . A computer-implemented method, comprising: detecting, by a processor device of a computer system, a charge parameter imbalance between rechargeable electrical energy storage packs of a vehicle, the electrical energy storage packs being independently connectable to a bi-directional DC/DC converter via a traction voltage bus; in response to detecting the imbalance and until a target charge parameter level is reached for each of the electrical energy storage packs: (A) connecting, by the processor device, one or more of the electrical energy storage packs to a bi-directional DC/DC converter connectable to a low voltage electrical energy storage to transfer energy from the one or more electrical energy storage pack to the low voltage electrical energy storage via the bi-directional DC/DC converter, (B) detecting, by the processor device, that either the low voltage electrical energy storage is at an upper-level capacity or that one of the one or more electrical energy storage pack is discharged to the target charge parameter level, (C) disconnecting, by the processor device, the one or more electrical energy storage pack from the bi-directional DC/DC converter, if the target charge parameter level is not reached for each of the electrical energy storage packs, (D) connecting, by the processor device, at least one further electrical energy storage pack to the bi-directional DC/DC converter to transfer energy from the low voltage electrical energy storage to the at least one further electrical energy storage pack via the bi-directional DC/DC converter, (E) detecting, by the processor device, that either the low voltage electrical energy storage is at lower-level capacity or that the one of the at least one further electrical energy storage pack is at the target charge parameter level, and (F) disconnecting, by the processor device, the at least one further electrical energy storage pack from the bi-directional DC/DC converter.
  3. 3 . The method of claim 2 , further comprising: detecting, by the processor device, that the low voltage electrical energy storage device is initially at the maximum capacity, wherein the method is initiated by connecting, by the processor device, a further electrical energy storage pack to the bi-directional DC/DC converter to transfer energy from the low voltage electrical energy storage to the further electrical energy storage pack via the bi-directional DC/DC converter.
  4. 4 . The method of claim 2 , further comprising: controlling, by the processor device, contactors connected to respective traction electrical energy storage packs and to a traction voltage bus connected to the bi-directional DC/DC converter, when connecting the electrical energy storage packs to the bi-directional DC/DC converter.
  5. 5 . The method of claim 2 , further comprising: detecting, by the processor device, that an electrical energy storage system comprising the electrical energy storage packs has been subject to service or repair, and in response, initiating the imbalance detection.
  6. 6 . The method of claim 2 , wherein the charge level parameter is at least one of state of charge and voltage of the electrical energy storage packs.
  7. 7 . The method of claim 2 , wherein the upper-level capacity is a maximum configured capacity of the low voltage electrical energy storage.
  8. 8 . The method of claim 2 , wherein the lower-level capacity is a minimum configured capacity of the low voltage electrical energy storage.
  9. 9 . The method of claim 2 , wherein the number of electrical energy storage packs is at least two.
  10. 10 . The method of claim 2 , wherein the electrical energy storage packs are connected to a common traction voltage bus via controllable, by the processor device, contactors.
  11. 11 . The method of claim 10 , wherein the bi-directional DC/DC converter is connected to the common traction voltage bus.
  12. 12 . The method of claim 11 , wherein the low voltage electrical energy storage is connected to the common traction voltage bus only via the bi-directional DC/DC converter.
  13. 13 . The method of claim 2 , wherein the low voltage electrical energy storage is a pre-existing low voltage electrical energy storage of the vehicle.
  14. 14 . The method of claim 2 , wherein the electrical energy storage packs are comprised in an electrical energy storage system providing propulsion electrical power to a vehicle drivetrain.
  15. 15 . The method of claim 2 , wherein the low voltage electrical energy storage is a 12-48 nominal voltage electrical energy storage.
  16. 16 . The method of claim 2 , comprising: controlling, by the processor device, contactors connected to respective traction electrical energy storage packs and to a traction voltage bus connected to the bi-directional DC/DC converter, when connecting the electrical energy storage packs to the bi-directional DC/DC converter, wherein: the charge level parameter is at least one of state of charge and voltage of the electrical energy storage packs; the upper-level capacity is a maximum configured capacity of the low voltage electrical energy storage; the lower-level capacity is a minimum configured capacity of the low voltage electrical energy storage; the number of electrical energy storage packs is at least three; the electrical energy storage packs are connected to a common traction voltage bus via contactors controllable by the processor device; the bi-directional DC/DC converter is connected to the common traction voltage bus; the low voltage electrical energy storage is connected to the common traction voltage bus only via the bi-directional DC/DC converter; the electrical energy storage packs are comprised in an electrical energy storage system providing propulsion electrical power to a vehicle drivetrain; and the low voltage electrical energy storage is a 12-48 nominal voltage electrical energy storage.
  17. 17 . A vehicle, comprising: a processor device of a computer system, configured to perform: detecting a charge parameter imbalance between rechargeable electrical energy storage packs of a vehicle, the electrical energy storage packs being independently connectable to a bi-directional DC/DC converter via a traction voltage bus; in response to detecting the imbalance and until a target charge parameter level is reached for each of the electrical energy storage packs: (A) connecting one or more of the electrical energy storage packs to a bi-directional DC/DC converter connectable to a low voltage electrical energy storage to transfer energy from the one or more electrical energy storage pack to the low voltage electrical energy storage via the bi-directional DC/DC converter, (B) detecting that either the low voltage electrical energy storage is at an upper-level capacity or that one of the one or more electrical energy storage pack is discharged to the target charge parameter level, (C) disconnecting the one or more electrical energy storage pack from the bi-directional DC/DC converter, if the target charge parameter level is not reached for each of the electrical energy storage packs, (D) connecting at least one further electrical energy storage pack to the bi-directional DC/DC converter to transfer energy from the low voltage electrical energy storage to the at least one further electrical energy storage pack via the bi-directional DC/DC converter, (E) detecting that either the low voltage electrical energy storage is at lower-level capacity or that the one of the at least one further electrical energy storage pack is at the target charge parameter level, and (F) disconnecting the at least one further electrical energy storage pack from the bi-directional DC/DC converter.

Description

TECHNICAL FIELD The disclosure relates generally to balancing of rechargeable electrical energy storages. In particular aspects, the disclosure relates to balancing of an electrical energy storage using a low voltage network. The disclosure can be applied in heavy-duty vehicles, such as trucks, buses, marine applications, and construction equipment. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle. BACKGROUND In heavy and medium duty vehicle applications multiple traction voltage battery packs are often installed in parallel to achieve high energy content. It is desirable to keep the voltage levels of the battery packs equal within some tolerance to avoid high inrush currents during connection sequences. It may further be desirable to keep the state of charge levels between the battery packs equal within some tolerance to ensure optimal energy availability typically limited by the weakest cell or battery pack. During usage and idle time of the vehicle the voltage and SOC levels can drift causing undesired behavior such as inrush or stray currents between packs and lowered energy availability. This leads to the need of energy balancing between the multiple packs. SUMMARY According to a first aspect of the disclosure, there is provided a computer system comprising a processor device configured to: detect a charge parameter imbalance between rechargeable electrical energy storage packs of a vehicle; in response to detecting the imbalance, the processor device is configured to, until each electrical energy storage pack is at a target charge parameter level, repeat: (A) connect one or more of the electrical energy storage packs to a bi-directional DC/DC converter connectable to a low voltage electrical energy storage to transfer energy from the one or more electrical energy storage pack to the low voltage electrical energy storage via the bi-directional DC/DC converter, (B) detect that either the low voltage electrical energy storage is at an upper-level capacity or that one of the one or more electrical energy storage pack is discharged to the target charge parameter level, (C) disconnect the one or more electrical energy storage pack from the bi-directional DC/DC converter, (D) connect at least one further electrical energy storage pack to the bi-directional DC/DC converter to transfer energy from the low voltage electrical energy storage to the at least one further electrical energy storage pack via the bi-directional DC/DC converter, (E) detect that either the low voltage electrical energy storage is at lower level capacity or that the one of the at least one further electrical energy storage pack is at the target charge parameter level, (F) disconnect the at least one further electrical energy storage pack from the bi-directional DC/DC converter. The first aspect of the disclosure may seek to balance the electrical energy storage packs in a more energy efficient way. A technical benefit may include that the energy is persevered within the vehicle and thus not be dissipated through heating a resistor or similar. Furthermore, the present disclosure provides for an onboard balancing method that reduces downtime of the vehicle. Advantageously, the balancing method can be performed even without external electrical grid connection. Still further, the method provides for balancing the electrical energy storage system after service or replacement without the need for pre-balancing before installation. Advantageously, the low voltage electrical energy storage of the vehicle may be a pre-existing low voltage electrical energy storage of the vehicle, thus there is no need for installing a further low voltage electrical energy storage in the vehicle. According to a second aspect of the disclosure, there is provided a computer-implemented method, comprising: detecting, by a processor device of a computer system, a charge parameter imbalance between rechargeable electrical energy storage packs of a vehicle; in response to detecting the imbalance and until a target charge parameter level is reached for each of the electrical energy storage packs, perform: (A) connecting, by the processor device, one or more of the electrical energy storage packs to a bi-directional DC/DC converter connectable to a low voltage electrical energy storage to transfer energy from the one or more electrical energy storage pack to the low voltage electrical energy storage via the bi-directional DC/DC converter, (B) detecting, by the processor device, that either the low voltage electrical energy storage is at an upper-level capacity or that one of the one or more electrical energy storage pack is discharged to the target charge parameter level, (C) disconnecting, by the processor device, the one or more electrical energy storage pack from the bi-directional DC/DC converter, if the target charge parameter level is not reached for each of the electrical energy