ESS system for balancing voltage and service life of battery pack unit

Abstract

The invention provides an ESS system for balancing voltage and service life of a battery pack unit, and relates to the technical field of battery control of an energy storage system. According to the ESS system for balancing the voltage and the service life of the battery pack unit, the converter is independently added to the battery pack unit on the battery pack, and the discharge capacity is controlled according to the service life state and the voltage of the battery pack, so that the independent conversion control of the battery pack unit and the active control of the whole unit pack are realized, and the usage amount of the battery packs is matched; therefore, the overall voltage balance and the service life balance of the battery pack in the ESS system are realized, and the use efficiency of the battery of the ESS system formed by taking the unit pack as a basic module is improved; moreover, through independent control of a unit battery pack, long-term balance control is realized, installation and management costs are reduced, economical efficiency is improved, and meanwhile, overall life reduction and thermal aging of the battery can be minimized. Compared with traditional resistance balance control, the energy loss is reduced, the overall service life and voltage balance are rapidly achieved, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of battery control for energy storage systems, and in particular to an ESS system for balancing the voltage and life of battery pack cells. Background Art

[0002] A battery pack typically consists of a battery module, a thermal management system, a battery management system (BMS), an electrical system, and structural components. Battery packs are used in diverse fields: for example, they are the "heart" of new energy electric vehicles, providing power and impacting range and safety. In energy storage systems, battery packs are used for emergency power supply and photovoltaic power generation, helping to store energy and improve energy efficiency. In industrial applications such as robotics and drones, battery packs provide stable power to support equipment operation.

[0003] In recent years, the technological advancements in new energy battery packs have led to the widespread use of energy storage systems (ESS) to ensure a stable supply and management of electrical energy. ESS systems store electrical energy in battery packs and deliver it when needed, thereby improving energy efficiency. ESS systems are used not only in fixed equipment such as industrial facilities but also in mobile equipment such as electric vehicles, industrial electric vehicles like excavators and forklifts, and electric agricultural machinery.

[0004] Figure 1 The battery structure of a current ESS system is shown. As shown in the figure, ESS battery packs are connected in series or parallel, and multiple battery packs are connected in parallel as modules. A battery pack is a collection of multiple battery cells.

[0005] However, this type of battery-based ESS system has the following problem: due to the impedance characteristics between battery cells and the impedance changes caused by temperature differences, the discharge amount of the battery pack cells cannot be controlled, resulting in voltage deviations between battery packs.

[0006] While existing battery management systems (BMS) use resistors to balance battery cells, they cannot address the issue of discharge rate variations caused by accumulated impedance differences over battery life, which in turn leads to lifespan variations between battery packs or modules. Furthermore, existing technologies struggle to effectively reduce voltage deviations between battery packs within an ESS, leading to reduced battery life and thermal aging damage.

[0007] Traditional battery cell balancing control relies on resistance control within the battery pack cells. However, due to the inability to accurately measure the internal resistance value of the battery cells, the control efficiency is low and it cannot solve the problems of battery pack voltage drop and shortened life.

[0008] To this end, the present invention has developed a new ESS system that balances the voltage and life of battery pack cells. Summary of the Invention

[0009] (1) Technical problems solved To address the shortcomings of the existing technology, the present invention provides an ESS system that balances the voltage and life of battery pack cells. This solves the problem that in existing ESS systems composed of batteries, impedance changes caused by impedance characteristics and temperature differences between battery cells make it impossible to control the discharge amount of battery pack cells, resulting in voltage deviation between battery packs. Furthermore, the existing technology is unable to effectively reduce the voltage deviation between battery packs in the ESS system, resulting in reduced battery life and thermal aging damage.

[0010] (2) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: an ESS system for balancing the voltage and life of battery pack cells, including multiple battery packs connected in series or parallel on a pack basis, and multiple battery modules connected in parallel on a module basis. The battery pack is composed of multiple battery cells, and each battery pack cell is equipped with an independent DC / DC converter for independently controlling the discharge amount according to the battery pack capacity during discharge. The ESS system further implements active balancing control of the battery modules through independent balancing control of the battery packs.

[0011] Preferably, each DC / DC converter connected to each of the above-mentioned battery pack units has the ability to perform differential discharge of each battery pack.

[0012] Through the above technical solution, the DC / DC converter can transfer energy to other battery packs by increasing the discharge capacity of a certain battery pack, thereby achieving overall voltage balance of the battery module.

[0013] Preferably, the ESS system further includes a battery management system (BMS) for monitoring and managing battery temperature, voltage and current information.

[0014] Through the above technical solution, the BMS uses sensors to monitor battery parameters such as voltage, current, and temperature in real time, ensuring that the battery operates within a safe range. This data helps the BMS calculate the battery voltage and lifespan, enabling precise battery management to prevent overcharging and overdischarging, and avoid damage from overheating or overloading. By balancing the charge and discharge process, the BMS can reduce variations between individual cells, maintain the consistency of the battery pack, and thus extend the life of the entire battery pack.

[0015] Preferably, the DC / DC converter adjusts the discharge amount according to the voltage (SOC, state of charge) of the battery pack to achieve voltage balance matching control.

[0016] Preferably, the battery pack with higher voltage transfers energy to the battery pack with lower voltage by increasing the discharge amount, thereby achieving overall voltage balance of the battery module.

[0017] Preferably, the DC / DC converter adjusts the discharge amount according to the state of life (SOH) of the battery pack to achieve life balance matching control.

[0018] Preferably, the battery pack with a higher state of life transfers energy to the battery pack with a lower state of life by increasing the discharge amount, thereby achieving overall life balance of the battery module.

[0019] (3) Beneficial effects The present invention provides an ESS system that balances the voltage and life of battery pack cells. It has the following beneficial effects: This ESS system, which balances the voltage and life of battery pack cells, adds converters to the battery packs and controls the discharge amount based on the battery pack's life state and voltage. This achieves independent conversion control of the battery pack cells and active control of the entire unit pack, thereby matching the usage of the battery packs. In this way, the overall voltage and life of the battery packs within the ESS system can be balanced, improving the battery efficiency of the ESS system composed of unit packs as basic modules. Furthermore, independent control of each battery pack enables long-term balancing, reducing installation and management costs and improving economic efficiency while minimizing overall battery lifespan degradation and thermal aging. Compared to traditional resistance balancing control, this invention reduces energy loss, quickly achieves overall lifespan and voltage balance, and extends battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the battery composition of the ESS system in the prior art.

[0021] Figure 2 Schematic diagram of the battery composition of the ESS system of the present invention.

[0022] Legend: 10, battery pack; 100, battery module; 20, DC / DC converter. DETAILED DESCRIPTION

[0023] like Figure 2 As shown, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] Example: An ESS system for balancing the voltage and life of battery pack cells includes a plurality of battery packs 10 connected in series or parallel on a pack basis, and a plurality of battery modules 100 connected in parallel on a module basis. The battery pack 10 is composed of multiple battery cells. In existing ESS systems, voltage deviations between battery packs 10 lead to temperature imbalances and lifespan differences, thereby reducing battery efficiency. In the technical solution of the present application, each battery pack cell is equipped with an independent DC / DC converter 20 for independently controlling the discharge amount according to the battery pack capacity during discharge. The ESS system further implements active balancing control of the battery modules through independent balancing control of the individual battery packs 10. At the same time, each DC / DC converter 20 connected to each of the battery pack units is capable of performing differential discharge of each of the battery packs 10 .

[0025] Specifically, the DC / DC converter 20 can adjust the discharge amount according to the voltage SOC of the battery pack 10 to achieve voltage balance matching control. The battery pack 10 with higher voltage transfers energy to the battery pack 10 with lower voltage by increasing the discharge amount, thereby achieving overall voltage balance of the battery module. The DC / DC converter 20 can also adjust the discharge amount according to the life state SOH of the battery pack 10 to achieve life balance matching control. The battery pack 10 with a higher life state transfers energy to the battery pack 10 with a lower life state by increasing the discharge amount, thereby achieving overall life balance of the battery module.

[0026] In summary, the DC / DC converter 20 adjusts the discharge amount of the high SOH or high voltage battery pack according to the SOH and voltage state of the battery pack, and charges the low SOH or low voltage battery pack, thereby achieving overall balance between the modules 100 and realizing active balance control of life and voltage.

[0027] In addition, the ESS system also includes a battery management system (BMS), which is used to monitor and manage the battery's temperature, voltage, and current information. It can also further optimize balance control through the battery information monitored by the battery management system (BMS).

[0028] Specifically, the battery management system (BMS) uses sensors to monitor battery parameters such as voltage, current, and temperature in real time, ensuring that the battery operates within a safe range. This data helps the BMS calculate the battery voltage and lifespan, enabling precise battery management to prevent overcharging and overdischarging, and avoid damage from overheating or overloading. By balancing the charge and discharge process, the BMS reduces variations between individual cells, maintaining consistency in the battery pack, and thus extending the lifespan of the entire battery pack.

[0029] In summary, the present invention adopts the method of adding an independent control part to the battery pack unit on the battery pack - adding an independent DC / DC converter to the battery pack unit, controlling the discharge amount according to SOH and voltage, achieving usage matching between battery packs, and realizing precise control and balanced adjustment of the discharge amount of the battery pack unit, thereby improving the overall voltage and life balance, improving battery utilization efficiency, and reducing installation and management costs.

[0030] Without significantly increasing capacity, long-term stable balance control can be achieved; at the same time, by optimizing battery life management, slowing down thermal aging and improving utilization efficiency, the loss cost caused by traditional battery performance degradation can be significantly reduced, which can reduce energy loss, quickly achieve overall balance, extend battery life, and reduce installation and management costs, thereby achieving cost savings in equipment installation and operation and maintenance costs, and ultimately achieving the goal of maximizing economic benefits.

[0031] Furthermore, while the present invention has a smaller capacity than existing ESS battery systems, it can also achieve long-term balance through active control of each battery cell. Taking into account the lifespan, degradation, and loss costs incurred by low utilization of existing batteries, it can reduce equipment installation and management costs, resulting in higher economic efficiency.

[0032] The device of the present invention is suitable for ESS systems using lithium-ion batteries and can be applied to the field of high-voltage and high-current batteries, including fixed equipment and mobile equipment such as electric vehicles, industrial electric vehicles and electric agricultural machinery.

[0033] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An ESS system for balancing battery pack unit voltage and life, comprising a plurality of battery packs (10) connected in series or in parallel in pack units, and a plurality of battery modules (100) connected in parallel in module units, characterized in that: The battery pack (10) is composed of a plurality of battery cells, each battery pack unit is equipped with an independent DC / DC converter (20) for independently controlling the discharge amount according to the battery pack capacity during discharge. The ESS system further realizes active balancing control of the battery module through independent balancing control of the unit battery pack (10).

2. The ESS system for balancing battery pack cell voltage and lifespan according to claim 1, characterized in that: Each DC / DC converter (20) connected to each of the battery pack units is capable of performing differential discharge of each battery pack (10).

3. The ESS system for balancing battery pack cell voltage and lifespan according to claim 1, characterized in that: The ESS system also includes a battery management system (BMS) for monitoring and managing battery temperature, voltage, and current information.

4. The ESS system for balancing battery pack cell voltage and lifespan according to claim 1, characterized in that: The DC / DC converter (20) adjusts the discharge amount according to the voltage (SOC) of the battery pack (10) to achieve voltage balance matching control.

5. The ESS system for balancing battery pack cell voltage and lifespan according to claim 4, characterized in that: The battery pack (10) with a higher voltage transfers energy to the battery pack (10) with a lower voltage by increasing the discharge amount, thereby achieving overall voltage balance of the battery module.

6. The ESS system for balancing battery pack cell voltage and lifespan according to claim 1, characterized in that: The DC / DC converter (20) adjusts the discharge amount according to the state of life (SOH) of the battery pack (10) to achieve life balance matching control.

7. The ESS system for balancing battery pack cell voltage and lifespan according to claim 6, characterized in that: The battery pack (10) with a higher state of life transfers energy to the battery pack (10) with a lower state of life by increasing the discharge amount, thereby achieving overall life balance of the battery module.

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