Parallel battery system compatible with multiple types of battery clusters and working method thereof

Abstract

This invention discloses a parallel battery system compatible with multiple types of battery clusters and its operating method, to overcome the limitations of power supply from a single energy storage medium and further avoid the problems of complex control and high cost of existing multi-energy storage medium systems. Specifically, this invention fully utilizes the advantages and disadvantages of different types of energy storage media to achieve compatible use of different types of energy storage media. First, the most suitable type of energy storage medium for the end-user application is selected as the main power supply in the entire power supply circuit; then, combining the advantages and disadvantages of this energy storage medium, the current working requirements of the load, and the end-user's usage conditions, other types of energy storage media are added for mixed use through circuit switching control; ultimately, this compensates for the problem of not being able to fully meet the end-user's needs due to the inherent defects of the main power supply.

Description

Technical Field

[0001] This invention specifically relates to a parallel battery system compatible with multiple types of battery clusters and its operating method, belonging to the technical field of battery power supply. Background Technology

[0002] There are many types of electrochemical energy storage media, each with its own advantages and disadvantages. No single energy storage medium can meet all operating conditions. For example, lithium iron phosphate (LFP) has a high energy density (100–120 Wh / kg) and a cycle life of around 3000 cycles, making it widely used in electric vehicles. However, its normal operating temperature range is only 0–55°C, and its performance degrades significantly below 0°C, requiring a heating system. Furthermore, LFP has poor fast-charging performance, which significantly impacts cycle life due to its relatively slow charging speed. Lithium titanate (LTI) batteries, on the other hand, can withstand a wide temperature range of -50°C to 65°C; they have a cycle life exceeding 10,000 cycles, offering a long lifespan; and they possess a very high charge / discharge rate (up to 10C or even 20C, more than five times that of batteries using ordinary graphite anode materials). However, LTI's energy density is relatively low (70–95 Wh / kg), and its high cost limits its application in power supply. Ternary lithium batteries have higher energy density (up to 200Wh / kg or more) and a higher discharge rate compared to lithium iron phosphate batteries. Their low-temperature performance, with a lower limit of -30℃, is superior to lithium iron phosphate. However, ternary lithium batteries gradually melt around 300℃, lower than lithium iron phosphate's 600℃; therefore, their safety is relatively lower. Lead-acid batteries, which are well-known, are safe and reliable, require no management system, and are low-cost; however, their low energy density, short lifespan, significant polarization, and memory effect limit their wide range of applications.

[0003] In the field of energy storage system power supply, due to various factors such as power variation of electrical load, customer usage requirements and diversity of working environment, energy storage systems are required to have higher charge / discharge rates, wider environmental adaptability and greater energy efficiency.

[0004] Existing technologies using a single energy storage medium struggle to meet diverse performance requirements, typically necessitating complex bypass systems to satisfy end-user needs. Furthermore, existing multi-energy storage medium hybrid power supply solutions employ complete isolation, resulting in complex control and high costs, hindering low-cost deployment, especially in high-power supply scenarios.

[0005] Chinese patent CN207398871U discloses a synchronous switching circuit for battery clusters, comprising: several battery packs, a DC-DC unit, an isolation resistor R0, a synchronization unit corresponding to each battery pack, and a battery management unit corresponding to each synchronization unit. This invention uses hardware circuitry to achieve synchronous switching of multiple battery packs; however, it cannot achieve switching control based on various performance requirements. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a parallel battery system compatible with multiple types of battery clusters.

[0007] The present invention also proposes a method for operating the above-mentioned parallel battery system.

[0008] Terminology Explanation:

[0009] SOP, or State of Power, refers to the battery's power state.

[0010] SOC (state of charge) is used to reflect the remaining capacity of a battery, and it is numerically defined as the ratio of the remaining capacity to the battery capacity.

[0011] Summary of the Invention: This invention provides a parallel battery system compatible with multiple types of battery clusters to solve the limitations of power supply by a single energy storage medium and further avoid the problems of complex control and high cost of existing multi-energy storage medium systems.

[0012] Specifically, this invention fully utilizes the advantages and disadvantages of different types of energy storage media to achieve compatible use of different types of energy storage media. First, the most suitable type of energy storage media for the end-user application is selected as the main power supply in the entire power supply circuit; then, combining the advantages and disadvantages of this energy storage media, the current working requirements of the load, and the end-user's usage conditions, other types of energy storage media are added for mixed use through circuit switching control; ultimately, this compensates for the problem of not being able to fully meet the end-user's needs due to the inherent defects of the main power supply.

[0013] The technical solution of this invention is as follows:

[0014] A parallel battery system compatible with multiple types of battery clusters, including power supplies k1, k2, ..., k n Positive isolation switch S + 1. S + 2、…、S + n Negative isolation switch S - 1. S - 2、…、S - n DC-DC isolation converter, fuse F n Multi-energy management controller and switch status monitor; where k1 is the main power supply, k2, ..., k n Auxiliary power supply;

[0015] Among them, power supply k x The positive terminal is connected in sequence to fuse F. x Positive isolation switch S+ x Then it serves as the positive terminal for power supply to the electrical equipment, power supply k x Negative terminal connected to negative terminal isolation switch S - x It then serves as the negative terminal for power supply to electrical equipment; x = 1, 2, ..., n; n ≥ 2;

[0016] The multi-energy management controller is connected to the DC-DC isolation converter and power supplies k1, k2, ..., k n The electrical equipment and switch status monitors are connected for data exchange and coordinated control between modules; the DC-DC isolation converter is located in S... + Between 1 and multiple energy management controllers;

[0017] The switch status monitor is connected to the positive and negative disconnect switches respectively, and is used to control the opening and closing actions and status monitoring of each disconnect switch according to the control instructions of the multi-energy management controller.

[0018] The type of energy storage medium for the main power supply is selected based on a comprehensive consideration of the type, power, working environment, and instantaneous characteristics of the electrical equipment in the actual application scenario, and the type that covers the widest range of actual operating conditions is chosen; in order to reduce the amount of auxiliary power supply used and thus reduce the investment cost of auxiliary power supply.

[0019] The auxiliary power supply is an optional configuration and can be selected based on the capability range of the main power supply.

[0020] The DC-DC isolation converter is configured only at the output of the main power supply for main power supply applications and voltage balancing control between the main power supply and other auxiliary power supplies.

[0021] The fuse is used for short-circuit and overload protection of each power supply.

[0022] The multi-energy management controller is used to coordinate the reasonable operation control between the main and auxiliary power supplies, DC-DC isolation converters, and electrical equipment according to the actual application conditions.

[0023] The multi-energy management controller is the highest-level control device in the system. It is an integrated circuit control board with a control chip as its core, with built-in control programs and communication and control functions. It is used to coordinate the reasonable operation control between the main and auxiliary power supplies, DC-DC isolation converters, switch status monitors, and electrical equipment according to the actual application conditions.

[0024] A switch status monitor, also known as a switch status monitoring controller, is an integrated circuit control board with a control chip at its core. It has built-in control programs and communication and control functions. It receives instructions from a multi-energy management controller and is used for driving control of disconnect switches and monitoring their open / closed / fault status.

[0025] Preferably, the energy storage medium of the main power supply is lithium iron phosphate, and the energy storage medium of the auxiliary power supply includes lithium titanate, supplementary lithium iron phosphate, ternary lithium battery, and lead-acid battery.

[0026] A method for operating the above-mentioned parallel battery system includes the following steps:

[0027] 1) The DC-DC isolated converter feeds back the maximum allowable output power P of the DC-DC isolated converter to the multi-energy management controller. dc The electrical equipment feeds back its power demand P to the multi-energy management controller. load ;

[0028] 2) After the multi-energy management controller comprehensively determines that each power supply is in a power-supplying state, it bases its operation on P... dc and P load Select a power source to put into operation; specifically:

[0029] a. When P1≥P load And P dc ≥P load At this time, the multi-energy management controller sends a working command to the switch status monitor, which then controls the positive isolating switch S. + 1 and negative isolation switch S + 1. When closed, the multi-energy management controller controls the operation of the DC-DC isolation converter, and the DC-DC isolation converter outputs the operating voltage required by the electrical equipment; among them, P1 is the SOP of the main power supply.

[0030] b. When P1≥P load And P dc <P load At that time, the multi-energy management controller selects auxiliary power supplies that meet the criteria, with the selection criterion being P. dc +P m ≥P load The multi-energy management controller sends operating commands to the main power supply and the selected auxiliary power supply; the switch status monitor controls the closing of the corresponding positive and negative isolating switches; the multi-energy management controller controls the operation of the DC-DC isolation converter, adjusts the consistency of the DC-DC isolation converter output voltage with the auxiliary power supply, and outputs the operating voltage required by the electrical equipment; among which, P m SOP for auxiliary power supply; m≥2;

[0031] If multiple auxiliary power supplies meet P dc +P m ≥P load Then, the auxiliary power supply with the highest power output will be selected for operation; when P dc +Pm <P load When this happens, the multi-energy management controller requests the electrical equipment to operate at reduced power.

[0032] c. When P1 < P load And P dc >P load At that time, the multi-energy management controller selects auxiliary power supplies that meet the criteria, with the selection criteria being P1+P. m ≥P load The multi-energy management controller sends working instructions to the main power supply and the selected auxiliary power supply; the switch status monitor controls the closing of the corresponding positive and negative isolating switches; the multi-energy management controller controls the operation of the DC-DC isolation converter, adjusts the consistency of the DC-DC isolation converter output voltage with the auxiliary power supply, and outputs the working voltage required by the electrical equipment.

[0033] d. When P1 < P load And P dc <P load Then, further determine P1 and P dc The size, when P1≥P dc When P1 < P, proceed to step b; dc Then proceed to step c.

[0034] Preferably, the operation method of the parallel battery system further includes a self-test step, specifically: after the system is powered on at low voltage, the multi-energy management controller and the switch status monitor perform a self-test; the power supply self-tests and reports the current status information, including SOC, SOP, voltage, and temperature; the switch status monitor reports that the open and closed states of each isolating switch are normal.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. This invention uses different types of energy storage media as power sources and designs reasonable control switching methods to achieve wide applicability of energy storage power supply applications in different scenarios; it has higher charge / discharge rates, wider environmental adaptability, and greater energy efficiency; it makes up for the limitations of single energy storage media applications; especially in some special application scenarios, where the electrical load has a large power discharge demand and its working environment changes significantly, this technical solution can better solve such problems.

[0037] 2. Considering the problem of different power supply types being unable to be used together due to different charge / discharge rates and charge / discharge speeds, this invention designs an isolation circuit for isolation and performs real-time status monitoring of the isolation switch in the circuit to avoid impact current damage between batteries caused by undesirable direct use of different battery types. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the battery system described in this invention;

[0039] Figure 2 This is a schematic diagram of the circuit principle of the battery system described in Example 1;

[0040] Figure 3 This is a flowchart illustrating the working method of the parallel battery system described in this invention.

[0041] The components include: 1. Multi-energy management controller; 2. DC-DC isolation converter; 3. Lithium iron phosphate main power supply; 4. Lithium iron titanate auxiliary power supply; 5. Switch status monitor; 6. Electrical equipment. Detailed Implementation

[0042] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings.

[0043] Example 1

[0044] like Figure 2 As shown.

[0045] A parallel battery system compatible with multiple types of battery clusters, including power supplies k1, k2, ..., k n Positive isolation switch S + 1. S + 2、…、S + n Negative isolation switch S - 1. S - 2、…、S - n 1. DC-DC isolation converter 2. Fuse F n 1. Multi-energy management controller; 5. Switch status monitor; where k1 is the main power supply, k2, ..., k n For auxiliary power supplies, this embodiment uses a lithium iron phosphate main power supply 3 and a lithium iron phosphate auxiliary power supply 4. Lithium iron phosphate has good safety and high energy density, and is used as the energy storage medium for the main power supply in this embodiment. Considering the poor discharge characteristics of lithium iron phosphate at low temperatures and the difficulty in achieving high-rate discharge, lithium titanate is selected as the first choice for auxiliary power supply to compensate for the low-temperature and high-rate discharge limitations of lithium iron phosphate. Furthermore, considering applications in other scenarios, ternary lithium batteries and lead-acid batteries are selected as the second and third choices for auxiliary power supplies, respectively.

[0046] Among them, power supply k x The positive terminal is connected in sequence to fuse F. x Positive isolation switch S + x It then serves as the positive power supply for electrical equipment 6, and the power supply k xNegative terminal connected to negative terminal isolation switch S - x It then serves as the negative power supply for electrical equipment 6; x = 1, 2, ..., n; in this embodiment, n = 4;

[0047] The multi-energy management controller 1 is connected to the DC-DC isolation converter 2 and the power supply k1, k2, ..., k n The electrical equipment 6 and switch status monitor 5 are connected for data exchange and coordinated control between various modules; the DC-DC isolation converter 2 is located in S + Between 1 and the multi-energy management controller 1;

[0048] The switch status monitor 5 is connected to the positive disconnect switch and the negative disconnect switch respectively, and is used to control the opening and closing actions and status monitoring of each disconnect switch according to the control instructions of the multi-energy management controller 1.

[0049] Example 2

[0050] like Figure 3 As shown.

[0051] A method for operating a parallel battery system as described in Example 1 includes the following steps:

[0052] 1) DC-DC isolation converter 2 feeds back the current maximum allowable output power P of DC-DC isolation converter 2 to multi-energy management controller 1. dc The electrical equipment feeds back the power demand P of the electrical equipment 6 to the multi-energy management controller 1. load ;

[0053] 2) After the multi-energy management controller 1 comprehensively determines that each power supply is in a power-supplying state, based on P... dc and P load Select a power source to put into operation; specifically:

[0054] a. When P1≥P load And P dc ≥P load At that time, the multi-energy management controller 1 sends a working command to the switch status monitor 5, and the switch status monitor 5 controls the positive isolation switch S. + 1 and negative isolation switch S + 1. When closed, the multi-energy management controller 1 controls the operation of the DC-DC isolation converter 2, and the DC-DC isolation converter 2 outputs the operating voltage required by the electrical equipment 6; where P1 is the SOP of the main power supply.

[0055] b. When P1≥P load And P dc <P loadAt that time, the multi-energy management controller 1 selects auxiliary power supplies that meet the criteria, the selection criteria being P. dc +P m ≥P load The multi-energy management controller 1 sends operating commands to the main power supply and the selected auxiliary power supply; the switch status monitor 5 controls the closing of the corresponding positive and negative isolating switches; the multi-energy management controller 1 controls the operation of the DC-DC isolation converter 2, adjusting the output voltage of the DC-DC isolation converter 2 to match the auxiliary power supply, and outputting the required operating voltage for the electrical equipment; where P m SOP for auxiliary power supply; 2≤m≤n;

[0056] If multiple auxiliary power supplies meet P dc +P m ≥P load Then, the auxiliary power supply with the highest power output will be selected for operation; when P dc +P m <P load When this happens, the multi-energy management controller 1 requests the electrical equipment 6 to operate at reduced power.

[0057] c. When P1 < P load And P dc >P load At that time, the multi-energy management controller 1 selects auxiliary power supplies that meet the criteria, with the selection criteria being P1+P. m ≥P load The multi-energy management controller 1 sends working instructions to the main power supply and the selected auxiliary power supply; the switch status monitor 5 controls the corresponding positive and negative isolation switches to close; the multi-energy management controller 1 controls the DC-DC isolation converter 2 to work, adjusts the output voltage of the DC-DC isolation converter 2 to match the auxiliary power supply, and outputs the working voltage required by the electrical equipment 6.

[0058] d. When P1 < P load And P dc <P load Then, further determine P1 and P dc The size, when P1≥P dc When P1 < P, proceed to step b; dc Then proceed to step c.

[0059] Before step a, there is a self-test step, specifically: after the system is powered on at low voltage, the multi-energy management controller 1 and the switch status monitor 5 perform self-tests; the power supply self-tests and reports the current status information, including SOC, SOP, voltage, and temperature; the switch status monitor 5 reports that the open and closed status of each disconnecting switch is normal.

Claims

1. A method for operating a parallel battery system compatible with multiple types of battery clusters, the parallel battery system comprising power supplies k1, k2, ..., k n Positive isolation switch S + 1. S + 2、…、S + n Negative isolation switch S - 1. S - 2、…、S - n DC-DC isolation converter, fuse F n Multi-energy management controller, switch status monitor; among which, k1 is the main power supply, k2, ..., k n Auxiliary power supply; Among them, power supply k x The positive terminal is connected in sequence to fuse F. x Positive isolation switch S + x Then it serves as the positive terminal for power supply to the electrical equipment, power supply k x Negative terminal connected to negative terminal isolation switch S - x It then serves as the negative terminal for power supply to electrical equipment; x = 1, 2, ..., n; n ≥ 2; The multi-energy management controller is connected to the DC-DC isolation converter and power supplies k1, k2, ..., k n The electrical equipment and switch status monitors are connected for data exchange and coordinated control between modules; the DC-DC isolation converter is located in S... + Between 1 and multiple energy management controllers; The switch status monitor is connected to the positive and negative disconnect switches respectively, and is used to control the opening and closing actions and status monitoring of each disconnect switch according to the control instructions of the multi-energy management controller. Its features include the following steps: 1) The DC-DC isolated converter feeds back the maximum allowable output power P of the DC-DC isolated converter to the multi-energy management controller. dc The electrical equipment feeds back its power demand P to the multi-energy management controller. load ; 2) After the multi-energy management controller comprehensively determines that each power supply is in a power-supplying state, it bases its operation on P... dc and P load Select a power source to put into operation; specifically: a. When P1≥P load And P dc ≥P load At this time, the multi-energy management controller sends a working command to the switch status monitor, which then controls the positive isolating switch S. + 1 and negative isolation switch S + 1. When closed, the multi-energy management controller controls the operation of the DC-DC isolation converter, and the DC-DC isolation converter outputs the operating voltage required by the electrical equipment; among them, P1 is the SOP of the main power supply. b. When P1≥P load And P dc <P load At that time, the multi-energy management controller selects auxiliary power supplies that meet the criteria, with the selection criterion being P. dc +P m ≥P load The multi-energy management controller sends operating commands to the main power supply and the selected auxiliary power supply; the switch status monitor controls the closing of the corresponding positive and negative isolating switches; the multi-energy management controller controls the operation of the DC-DC isolation converter, adjusts the consistency of the DC-DC isolation converter output voltage with the auxiliary power supply, and outputs the operating voltage required by the electrical equipment; among which, P m SOP for auxiliary power supply; m≥2; If multiple auxiliary power supplies meet P dc +P m ≥P load Then, the auxiliary power supply with the highest power output will be selected for operation; when P dc +P m <P load When this happens, the multi-energy management controller requests the electrical equipment to operate at reduced power. c. When P1 < P load And P dc >P load At that time, the multi-energy management controller selects auxiliary power supplies that meet the criteria, with the selection criteria being P1+P. m ≥P load The multi-energy management controller sends working instructions to the main power supply and the selected auxiliary power supply; the switch status monitor controls the closing of the corresponding positive and negative isolating switches; the multi-energy management controller controls the operation of the DC-DC isolation converter, adjusts the consistency of the DC-DC isolation converter output voltage with the auxiliary power supply, and outputs the working voltage required by the electrical equipment. d. When P1 < P load And P dc <P load Then, further determine P1 and P dc The size, when P1≥P dc When P1 < P, proceed to step b; dc Then proceed to step c.

2. The operating method of the parallel battery system according to claim 1, characterized in that, The main power supply uses lithium iron phosphate as its energy storage medium, while the auxiliary power supply uses lithium titanate, supplementary lithium iron phosphate, ternary lithium batteries, and lead-acid batteries as its energy storage medium.

3. The operating method of the parallel battery system according to claim 1, characterized in that, The operation method of the parallel battery system also includes a self-test step. Specifically, after the system is powered on at low voltage, the multi-energy management controller and switch status monitor perform a self-test; the power supply self-tests and broadcasts the current status information, including SOC, SOP, voltage, and temperature. The switch status monitor reports that the open and closed status of each disconnect switch is normal.

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