CN-121986399-A - Lead-acid battery management system

Abstract

A lead-acid Battery Management System (BMS) for a battery system including a plurality of battery packs of at least one lead-acid battery and a method of operating the BMS, the battery management system including at least one control device configured to electrically integrate and isolate each of the batteries from a battery string, and a controller configured to control the control device to independently control charging and discharging of each of the batteries. In some cases, the controller is configured to determine an input power available to charge the battery system, determine that at least one of the battery packs of batteries is chargeable above a charge threshold based on the determined input power, and selectively charge at least one of the battery packs of at least one battery. In some cases, the BMS is configured to independently overcharge the battery. In some cases, the BMS is configured to modify the discharging of the at least one battery based on the determined charging characteristics.

Inventors

• S. Mackenzie
• S. Christie
• E. S. Homberg

Assignees

• 阿克爱科蒂夫有限公司

Dates

Publication Date

20260505

Application Date

20240930

Priority Date

20230928

Claims (20)

1. 1. A lead-acid battery management system for charging a battery system, the battery system comprising a plurality of battery packs, each battery pack having at least one lead-acid battery, the battery management system comprising: At least one control device configured to electrically integrate and isolate each of the battery packs of at least one battery from the battery system, and A controller configured to control the control device to independently control the charge and discharge of each of the battery packs of at least one battery, Wherein the controller is configured to: Determining an input power usable to charge the battery system; Determining that at least one of the battery packs of the battery is chargeable above a charge threshold based on the determined input power, and At least one of the battery packs of at least one battery is selectively charged.
2. 2. The lead acid battery management system of claim 1, comprising the steps of: determining the number of said battery packs of at least one battery to be charged based on said determined input power, and The battery pack of the determined number of at least one battery is selectively charged.
3. 3. The lead-acid battery management system of claim 1 or 2, wherein the charge threshold is a battery cell charge potential threshold.
4. 4. The lead-acid battery management system of claim 1 or 2, wherein the charge threshold is a desired positive half cell overpotential.
5. 5. The lead-acid battery management system of any of claims 1 to 4, wherein the charge threshold is determined based on a desired positive half cell overpotential.
6. 6. The lead-acid battery management system of claim 4 or claim 5, wherein the desired positive half cell overpotential threshold is any one or more of at least 100 mV, at least 150 mV, or at least 200 mV.
7. 7. The lead-acid battery management system of claim 5 or claim 6, wherein the charge threshold is a threshold that depends on an electrical characteristic of the lead-acid battery of the positive half-cell overpotential.
8. 8. The lead-acid battery management system of any of claims 4 to 7, wherein the selective charging of the at least one battery pack of at least one battery is controlled to achieve the desired positive half-cell overpotential.
9. 9. The lead-acid battery management system of any of claims 1 to 8, wherein the controller is configured to control a charge rate to maintain charging above the charge threshold.
10. 10. The lead-acid battery management system of claims 1-9, wherein the charge threshold is a minimum charge current.
11. 11. The lead-acid battery management system of claim 10, wherein the minimum charging current is based on a capacity of each of the plurality of battery packs of at least one battery.
12. 12. The lead-acid battery management system of claim 10 or 11, wherein the minimum charging current is predetermined.
13. 13. The lead-acid battery management system of claim 12, wherein the minimum charge current threshold comprises a charge rate, optionally wherein the charge rate is based on 5C capacity of the plurality of battery packs of at least one battery.
14. 14. The lead-acid battery management system of claim 12 or 13, wherein the minimum charge current threshold is between 0.7C and 1.4C, optionally at least 1C.
15. 15. The lead-acid battery management system of any of claims 1 to 14, wherein the charge threshold is applied below a threshold state of charge of each battery pack of at least one battery.
16. 16. The lead acid battery management system of claim 15, wherein the threshold state of charge is any of 40%, 45%, 50%, 55%, or 60%.
17. 17. The lead-acid battery management system of claims 1-16, comprising a charger, wherein determining an input power availability comprises determining a power rating of the charger.
18. 18. The lead-acid battery management system of claim 1 to 17 wherein determining available input power comprises receiving one or more measurements and determining the available input power based on the one or more measurements.
19. 19. The lead battery management system of claims 1-18, wherein the battery pack of at least one battery is connected in parallel to the battery system.
20. 20. The lead-acid battery management system of claims 1-19, wherein the controller is configured to monitor the state of charge of each of the battery packs of at least one battery, optionally with a coulomb counter.

Description

Lead-acid battery management system Technical Field The present disclosure relates generally to battery management systems for lead acid batteries and methods of controlling battery management systems. Background Battery energy storage is increasingly becoming a popular complement to Home Energy Management (HEM) systems and/or Energy Storage Systems (ESS). Lead Acid Batteries (LABs) typically include a plurality of inaccessible battery cells (cells) within each battery and provide a low cost solution for energy storage. Historically, however, LABs have had a poorer service life and low depth of discharge (typically only 40% to 60% of the charge in the battery can be discharged) and/or battery failure when compared to techniques such as lithium ion. Lead acid batteries are typically arranged into battery packs (also known as strings) or modules. The battery pack allows combining multiple batteries to increase overall stored energy and/or provide a greater output voltage and/or a greater output current. The battery packs may be arranged with cells connected in series, parallel, or both. Typically, the lead acid batteries are arranged in a series configuration, up to about 1000 VDC, and then a second (and more) parallel battery pack will be added if additional capacity is required. Parallel battery packs allow the battery to be charged and discharged in a combined action. In this way, each battery within the battery system will ideally discharge the same amount, and charge the same amount, so that each battery in the system will always be in the same state of charge. In practice, there is a great difference between similar lead acid batteries. For example, in a series string of cells, individual cells within the string will be exposed to different charge/discharge voltages. A battery that is subjected to the highest charge voltage will have a higher gassing rate and be exposed to a higher degree of water loss and grid corrosion than a battery with the lowest charge voltage, thereby altering its electrical performance. In parallel battery strings, different battery voltages and/or impedances will result in different charge and discharge currents and thus different states of charge between the batteries within the battery string. LABs that are subjected to the highest charge and discharge currents will experience larger fluctuations in the state of charge window and therefore will work harder and wear out faster than other components of the battery string. Different types of LABs may be used. Such as prismatic cells, absorptive glass fiber separators (AGM), and bipolar cells. Square or monopolar cells have separate positive and negative electrodes, with electrical connections between adjacent cells being required. A bipolar battery has a plurality of battery cells arranged in series, with adjacent battery cells sharing an electrode, such that one battery cell negative electrode and another battery cell positive electrode are positioned immediately adjacent to each other. US9711976B2 shows a prior art system using lead acid batteries. The lead-acid batteries are arranged in a series string of batteries, and a state of charge (SoC) model is used to determine when to apply equalization charge to equalize the SoC of all the batteries in the series string. US9711976B2 proposes how to estimate the SoC of each battery and reduce the number of required equalization charges. Maintaining the health of LABs requires careful management of charging and discharging and consideration of the state of the electrolyte between LABs. The management of LABs is different from other battery types that use different chemistries (e.g., lithium ions). Furthermore, in many cases, there are conflicting requirements such that a Battery Management System (BMS) must be carefully designed to improve overall performance. Due to the different chemistries of the batteries, the required operating parameters of the batteries and the different battery arrangements, a universal battery management system cannot be applied or used in these different battery types. Currently, lithium ion or hybrid battery packs have been preferred for energy storage because these techniques may have a longer life and/or deeper cycling. It is an object of the present disclosure to provide a BMS for LABs and/or a method of operating a BMS for LABs that extends the useful lifetime of the LABs or at least substantially alleviates the above-mentioned product limitations. Disclosure of Invention Aspects of the present disclosure address one or more of the above-described problems by providing a lead-acid battery management system and/or method of managing a plurality of lead-acid batteries that increases the useful life of the lead-acid batteries in a battery system, or addresses one or more of the problems associated with prior art systems, or at least provides an option. Aspects of the present disclosure address one or more of the above problems by providing a lead-acid bat