CN113328490A

CN113328490A - Power supply system

Info

Publication number: CN113328490A
Application number: CN202110585564.6A
Authority: CN
Inventors: 陈四雄; 胡雄伟; 王定富; 许勇枝; 苏先进
Original assignee: Zhangzhou Kehua Technology Co Ltd; Kehua Data Co Ltd
Current assignee: Zhangzhou Kehua Technology Co Ltd; Kehua Data Co Ltd
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2021-08-31

Abstract

The invention provides a power supply system, which comprises a plurality of battery clusters, an access unit and a first BMS management unit; the battery cluster comprises a plurality of battery packs and a second BMS management unit; the battery pack includes a battery module, a first DC/DC converter, and a third BMS management unit; the third BMS management unit acquires external characteristic parameters of each battery cell unit; the second BMS management unit is in signal connection with each third BMS management unit and judges whether each battery pack is abnormal or not, and the second BMS management unit also receives a cluster of output targets to control the electric output parameters of each battery pack; the first BMS management unit is in signal connection with each second BMS management unit to acquire the abnormal information of each battery pack in each battery cluster, and opens and closes the corresponding cluster access switch and sends a cluster output target to the second BMS management unit of each battery cluster. The power supply system is suitable for capacity expansion and has better personnel safety, and is convenient to wire and suitable for handling the battery fault condition.

Description

Power supply system

Technical Field

The invention relates to the technical field of batteries and battery power supply, in particular to a power supply system.

Background

Currently, the UPS is widely adopted. In the event of a mains power anomaly, the UPS typically switches to a battery-powered state to ensure uninterrupted power supply to the load. As the load level increases, the output power of the UPS also needs to increase, which requires that the output power of the battery pack is also matched in the battery-powered state.

In the conventional UPS, the battery assembly is generally composed of a plurality of battery packs, and when capacity expansion is required, the battery assembly is generally implemented by connecting more battery packs in series or by using a battery pack with more single batteries. However, the voltage gain of the DC/DC converter inside the UPS is not large, so that more batteries need to be connected in series during capacity expansion, which results in higher output voltage of the battery pack, and this has a certain influence on the safety of personnel operating and maintaining the battery pack.

Disclosure of Invention

The present invention is directed to overcoming at least one of the disadvantages or problems of the related art, and providing a power supply system suitable for capacity expansion and having better personnel safety.

In order to achieve the purpose, the technical scheme of the invention is as follows: a power supply system comprising: the system comprises a plurality of battery clusters, an access unit and a first BMS management unit; the battery cluster has a cluster connection end and includes a plurality of battery packs connected to each other, and a second BMS management unit; the battery pack includes a battery module, a first DC/DC converter, and a third BMS management unit; the battery module comprises a plurality of battery cell units which are connected in series; the low-voltage side of the first DC/DC converter is connected with the battery module, and the high-voltage side of the first DC/DC converter forms a pack connecting end of the battery pack and is used for realizing voltage conversion between the battery module and the pack connecting end; the third BMS management unit is used for acquiring external characteristic parameters of each battery cell unit; wherein, each battery pack establishes an electrical connection relationship through the pack connection end and defines the cluster connection end; the second BMS management unit is in signal connection with a third BMS management unit of each battery pack of the battery cluster where the second BMS management unit is located so as to judge whether each battery pack is abnormal or not according to the external characteristic parameters of the cell unit of each battery pack; the second BMS management unit further receiving a cluster of output targets to control an electrical output parameter of each battery pack; the access unit is used for accessing each battery cluster and comprises a plurality of cluster access switches correspondingly connected with the cluster connecting ends of each battery cluster; and the first BMS management unit is in signal connection with the second BMS management units of the battery clusters to acquire the abnormal information of the battery packs in the battery clusters, and opens and closes the corresponding cluster access switches according to the abnormal information and sends the corresponding cluster output targets to the second BMS management units of the battery clusters.

Further, the pack connection ends of the respective battery packs are connected in parallel to each other at a common end, which constitutes a cluster connection end of the battery cluster.

Further, the cluster output target is a cluster output power given value; the second BMS managing unit cutting off all the battery packs in the corresponding battery cluster when the cluster output target is zero; the second BMS managing unit cuts off the abnormal battery pack in the corresponding battery cluster when the cluster output target is not zero, and PWM-modulates the first DC/DC converters in the other battery packs according to the cluster output target to adjust the output power of the corresponding battery cluster by adjusting the output voltage and the output current of the corresponding battery pack.

Further, the first BMS determining an abnormal degree of each battery cluster based on the number of abnormal battery packs in the battery cluster, and assigning and transmitting a corresponding cluster output target to each battery cluster in combination with the abnormal degree and a current system output target; the first BMS management unit closes a cluster access switch corresponding to the battery cluster when all battery packs in the battery cluster are abnormal, and allocates and sends the cluster output target with a value of zero to a corresponding second BMS management unit; and the first BMS management unit keeps turning on a cluster access switch corresponding to the battery cluster when a non-abnormal battery pack exists in the battery cluster, and allocates and sends the cluster output target with a value not equal to zero to a corresponding second BMS management unit.

Further, the first BMS assigning and transmitting the cluster output target, the value of which is not zero, to each battery cluster maintaining access to the access unit according to a weighting principle.

Furthermore, the battery pack also comprises a plurality of equalizing circuits, each equalizing circuit is connected between two adjacent battery cell units in series and comprises an equalizing resistor and an equalizing switch which are connected with each other in series; the external characteristic parameters comprise voltages of the battery cell units, and the third BMS management unit further opens and closes corresponding equalization switches according to the voltages of the battery cell units so as to perform voltage equalization on the corresponding battery cell units.

Further, the external characteristic parameters include voltage, current and temperature; and the second BMS management unit also calculates the SOC and/or SOH of each battery pack according to the external characteristic parameters of the battery cell unit of each battery pack.

Further, the maximum output voltage of each battery module is lower than 65V; the number of the battery cell units in each battery module is the same, and each battery cell unit is composed of two single lithium batteries which are connected in parallel.

Furthermore, the access unit is provided with a first end and a second end, the first end of the access unit is connected with each battery cluster, and the second end of the access unit is connected with the first end through a corresponding cluster access switch; the first DC/DC converter in each battery pack is a bidirectional DC/DC converter; the power supply system further comprises an inverter device, wherein the inverter device is provided with a battery end and comprises a direct current bus, a second DC/DC converter and a second DC/DC control unit; the battery end is connected with the second end of the access unit so as to be connected with each battery cluster; the second DC/DC converter is a bidirectional DC/DC converter, and two sides of the second DC/DC converter are respectively connected with the direct current bus and the battery end and used for realizing voltage conversion between the direct current bus and the battery end; the second DC/DC control unit is used for controlling the second DC/DC converter to be kept on; the battery cluster also comprises a first voltage collector which is used for collecting the voltage of the cluster connecting end; each of the battery packs includes a first DC/DC control unit for controlling an operation direction of a corresponding first DC/DC converter; each first DC/DC control unit is in signal connection with the first voltage collector and controls the corresponding first DC/DC converter to work in the discharging direction when the voltage of the cluster connecting end is lower than a first threshold value, so that the corresponding battery module discharges to the converter device; when the voltage of the cluster connecting end is higher than a second threshold value, each first DC/DC control unit controls the corresponding first DC/DC converter to work in the charging direction so as to enable the corresponding battery module to be charged by the converter device; wherein the first threshold is less than or equal to a second threshold; the converter device also comprises a second voltage collector for collecting the voltage of the direct current bus; the second DC/DC control unit is connected with the second voltage collector to obtain the voltage of the direct current bus; the second DC/DC control unit controls the second DC/DC converter to work in a discharging direction when the voltage of the direct current bus is lower than a third threshold; the second DC/DC control unit controls the second DC/DC converter to work in a charging direction when the voltage of the direct current bus is higher than a fourth threshold value; wherein the third threshold is less than or equal to a fourth threshold.

Further, the converter device further comprises an AC/DC converter and a DC/AC converter; the direct current sides of the AC/DC converter and the DC/AC converter are both connected with the direct current bus, the alternating current side of the AC/DC converter is connected with an alternating current power supply, and the alternating current side of the DC/AC converter outputs alternating current; the high-voltage side of the second DC/DC converter is connected with the direct-current bus, and the low-voltage side of the second DC/DC converter is connected with the battery end.

Compared with the prior art, the invention has the beneficial effects that:

(1) the power supply system comprises a plurality of battery clusters, each battery cluster comprises a plurality of battery packs, each battery pack comprises a first DC/DC converter, and the first DC/DC converters are coupled with the battery modules to convert and output voltages of the battery modules, so that the capacity expansion of the power supply system applying the battery packs and the battery clusters is not required to be realized by greatly improving the output voltages of the battery modules. In other words, under the condition that the battery module outputs lower voltage, the battery pack can still keep certain output voltage during working so as to meet the requirement of a power supply system; when maintenance is needed, the battery pack can be maintained safely due to the fact that the output voltage of the battery module is not high. Therefore, the structure effectively improves the personnel safety of the battery pack during maintenance and operation, so that the corresponding power supply system is suitable for capacity expansion without worrying about the personnel safety.

In addition, the power supply system further adopts a three-level BMS management architecture on the basis, the three-level BMS management units are respectively positioned at a battery pack level, a battery cluster level and a power supply system level and face the battery cell unit, the battery pack and the battery cluster to perform corresponding BMS management, so that the power supply system is further convenient for capacity expansion due to other advantages.

Particularly, because the battery package is provided with the third BMS management unit for acquiring the external characteristic parameters of each battery cell unit, the second BMS management unit can acquire the external characteristic parameters of each battery cell unit only by communicating with each third BMS management unit to judge whether each battery package is abnormal, therefore, the second BMS management unit is not required to be connected to each battery cell unit through a large number of wire harnesses, the connection relation of signal lines in the battery cluster is simple and not easy to make mistakes, and because the signal lines are short, the conditions of signal interference and time delay can be effectively improved, the management of the battery cluster is facilitated, and the capacity expansion is facilitated.

Furthermore, the power supply system of the present invention employs a three-level BMS management architecture that communicates with each other, each level BMS management unit manages a sub-level battery level according to information reported by the sub-level BMS management units, for example, the third BMS management unit is located at a battery pack level and can be used to manage each cell unit, the second BMS management unit is located at a battery cluster level and is used to manage each battery pack, and the first BMS management unit is located at a power supply system level and is used to manage each battery cluster, so that a situation that a certain battery level automatically cuts off output after detecting that a certain degree of self-fault exists, and further, a large output pressure is applied to other parts of the same battery level, does not occur. For example, in the battery cluster level, if an abnormal or faulty battery pack exists in a certain battery cluster, and the BMS management unit in the battery cluster controls the battery cluster to directly quit the power supply output, a large output pressure may exist in other battery clusters of the same level. At this time, there may be a case that only a part of the battery packs in the battery cluster are abnormal and a part of the battery packs still exist and are suitable for power supply output, so that the part of the battery packs still suitable for power supply output is greatly wasted. In actual configuration, it is considered that it is difficult to implement communication between each battery cluster and any other battery cluster, which may cause that each battery cluster cannot know the operation condition of other battery clusters and correspondingly adjust its output by using a battery pack that can still supply power, and thus cannot cope with the above-mentioned waste phenomenon and solve the problem.

In the invention, the second BMS management unit uploads the abnormal information of the battery packs in the corresponding battery clusters to the first BMS management unit, so that the first BMS management unit can accurately acquire the abnormal information of the battery packs in the battery clusters and carry out global control on the battery clusters according to the abnormal information, wherein the abnormal information comprises whether each battery cluster is accessed and power supply output and a cluster output target which is required to be achieved by each battery cluster accessed and power supply output; then, the second BMS that receives the cluster output target may control the electrical output parameters of the battery packs in the battery cluster that are still suitable for power output, so that the battery packs are commonly matched and the battery cluster achieves the cluster output target, thereby fully utilizing all available battery packs in the power supply system, effectively achieving the operation purpose of the entire system, and improving the stability of the power supply system. In other words, the three-level BMS management architecture of the power supply system respectively adopts an upward reporting mechanism and a downward management mechanism at the communication level and the control level and effectively combines the two mechanisms, thereby solving the defect that the battery pack is not fully utilized possibly existing after the capacity expansion of the power supply system, and enabling the power supply system to be suitable for the capacity expansion.

It can also be seen that, because the battery parts in the power supply system are well-arranged, the battery pack, the battery cluster and the whole power supply system are provided with the BMS management units of corresponding levels, so that the parts are respectively configured in a modular manner, and the battery parts of the whole power supply system are well managed.

(2) The package link of battery package connects in parallel each other in order to define out the cluster link of battery cluster for each battery package has formed the battery cluster through parallelly connected, even if the battery module of battery package contains the electric core unit quantity less, battery package output voltage is lower, can also effectively improve the discharge performance of battery cluster, is particularly useful for the uninterrupted power source application of power supply system.

(3) The cluster output target is a cluster output power set value, and each second BMS management unit correspondingly cuts off an abnormal battery pack according to the cluster output target and performs PWM modulation on each first DC/DC converter according to the cluster output target to adjust the output voltage and current of each battery pack so as to adjust the output power of the corresponding battery cluster. In other words, the second BMS controlling unit may control whether the battery pack supplies power for output by using the switch of the first DC/DC converter without setting a dedicated charging/discharging control switch, thereby reducing the number of switches required to be set for the battery pack, improving the utilization rate of the switches, reducing the cost of the battery pack, and further being suitable for capacity expansion of the power supply system.

(4) The first BMS management unit determines the abnormal degree of each battery cluster according to the number of the abnormal battery packs in each battery cluster, so that a reasonable cluster output target corresponding to the abnormal degree of each battery cluster can be distributed according to the abnormal degree, and the full utilization of each battery pack is realized.

(5) The first BMS assigning a corresponding cluster output target to each of the accessed battery clusters according to a weighting rule, in other words, a cluster output target of a battery cluster with a high abnormal battery pack storage amount is low, and a cluster output target of a battery cluster with a high non-abnormal battery pack storage amount is high, which can prevent rapid degradation of a part of battery packs under a homogenization rule, and is adapted to maintain each of the battery packs to have substantially the same life.

(6) The battery pack is provided with an equalization circuit, and the third BMS management unit opens and closes corresponding equalization switches according to the voltage of each battery cell unit so as to perform voltage equalization on the corresponding battery cell units, so that the service life of each battery cell unit can be effectively prolonged.

(7) The second BMS management unit calculates the SOC and the SOH of each battery pack according to the external characteristic parameters of the battery cell unit of each battery pack, and provides data support for the aspects of charge and discharge control, battery life evaluation and the like of the battery packs.

(8) The maximum output voltage of the battery pack is lower than 65V, and the safety of personnel maintenance is guaranteed. The battery cell unit is composed of two single lithium batteries which are connected in parallel, so that the current level of the battery cell unit which can be loaded is improved, the service life is long, the discharge is stable, and the discharge performance of the battery pack is improved. The number of the battery cell units in each battery module is the same, so that the parallel circulating current condition can be prevented to a certain degree.

(9) The power supply system comprises a converter, and the battery end of the converter is connected into each battery cluster through an access unit, so that direct current electric energy of each battery cluster can be introduced and can be widely applied through corresponding conversion. In addition, each battery cluster is connected to the battery end of the converter device instead of a direct current bus, the existing converter device is not required to be modified, and the universality is good.

On the basis that the battery pack is correspondingly additionally provided with the bidirectional DC/DC converters, the invention is further provided with a first DC/DC control unit, and the first DC/DC control unit can control the working direction of each first DC/DC converter and match the operation requirement of the converter device only by simply comparing the voltage of the cluster connecting end with a preset threshold value. Specifically, the reason is that each battery cluster is electrically coupled with the converter device to discharge electricity to the converter device or charge electricity to the converter device, and each battery cluster is connected with the converter device through a cluster connecting end, so that the operation requirement of the converter device can be mapped to the voltage of the cluster connecting end, and the control unit can obtain the operation requirement of the converter device and perform corresponding control action to match the operation requirement only according to the cluster connecting end voltage.

In other words, the control of the first DC/DC converter in each battery pack can be independent of the control of the converter, and each battery pack can be matched with the operation requirement of the power supply system without establishing a direct communication connection with the converter through an industrial control bus and providing a complex control algorithm, which is particularly suitable for reducing the complexity of the communication layer and the control layer when the battery pack is actually applied, and reducing the difficulty of field wiring when the battery pack is large in number, so that the capacity of the power supply system is easily expanded.

Moreover, the power supply system also carries out key configuration on the converter, namely, the second DC/DC control unit controls the second DC/DC converter to be kept on when the converter works, so that the direct-current bus voltage suitable for reflecting the operation requirement of the converter can be transmitted to the cluster connecting end of each battery cluster through the second DC/DC converter, the fact that each battery cluster can obtain the effective cluster connecting end voltage capable of mapping the operation requirement of the converter is ensured, the first DC/DC control unit effectively controls the first DC/DC converter to match the operation requirement of the converter, and stable operation of the power supply system is further ensured.

In addition, the second DC/DC control unit controls the working direction of the second DC/DC converter by collecting the voltage of the direct-current bus, and the stability is high.

(10) The inverter device has an AC/DC converter and a DC/AC converter therein, so that the power supply system substantially constitutes an UPS power supply system suitable for capacity expansion, and can stably supply power to a load in a battery power supply state.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a topology diagram of a power supply system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a battery cluster according to an embodiment of the present invention;

FIG. 3 is a topology diagram of a battery cluster according to an embodiment of the present invention;

FIG. 4 is a topology diagram of a battery pack according to an embodiment of the present invention;

FIG. 5 is another topology of a battery pack according to an embodiment of the present invention;

fig. 6 is another topology diagram of the power supply system according to the embodiment of the present invention.

Description of reference numerals:

a battery cluster 100; a tuft connecting end 101; a battery pack 110; packet connection end 110A; a battery module 111; a cell unit 111A; a first DC/DC converter 112; a first DC/DC controller 112A; an equalizing circuit 113; an equalizing resistance 113A; an equalization switch 113B; a third BMS management unit 114; a second BMS management unit 120; a first voltage collector 130; an access unit 200; a first BMS management unit 300; a deflector 400; a battery terminal 401; an AC/DC converter 410; a DC/AC converter 420; a second DC/DC converter 430; a second DC/DC controller 440; a second voltage collector 450.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are presently preferred embodiments of the invention and are not to be taken as an exclusion of other embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the claims, the specification and the drawings of the present invention, unless otherwise expressly limited, the terms "first", "second" or "third", etc. are used for distinguishing between different items and not for describing a particular sequence.

In the claims, the specification and the drawings of the present invention, the terms "including", "having" and their variants, if used, are intended to be inclusive and not limiting.

In the claims, the specification and the drawings of the present invention, unless otherwise specifically limited, the term "connected", as used herein, may include a direct connection or an indirect connection; the term "coupled", as used herein, means that the two electrical modules have a particular circuit function when connected.

Referring to fig. 1, an embodiment of the present invention provides a power supply system including a plurality of battery clusters 100, an access unit 200, and a first BMS management unit 300.

As shown in fig. 2 to 3, the battery cluster 100 has a cluster connection terminal 101 and includes a plurality of battery packs 110 and a second BMS management unit 120 connected to each other.

As shown in fig. 3 to 5, the battery pack 110 includes a battery module 111, a first DC/DC converter 112, a plurality of balancing circuits 113, and a third BMS management unit 114.

Referring to fig. 3 and 5, the battery module 111 includes a plurality of cell units 111A connected in series. In this embodiment, the maximum output voltage of the battery module 111 is lower than 65V, so that the safety of personnel maintenance is ensured. The number of the cell units 111A in each battery module 111 is the same, and the parallel circulating current can be prevented to a certain extent. Each cell unit 111A is formed by two single lithium batteries connected in parallel with each other, as shown in fig. 5, which improves the current level of the load that can be loaded by the cell unit 111A, and has a long life and stable discharge, thereby improving the discharge performance of the battery pack 110.

Referring to fig. 3 and 4, the low voltage side of the first DC/DC converter 112 is connected to the battery module 111, and the high voltage side thereof forms a pack connection terminal 110A of the battery pack 110, and is used to convert the voltage between the battery module 111 and the pack connection terminal 110A. In this embodiment, the first DC/DC converter 112 is a bidirectional DC/DC converter, which can be an existing converter and is not limited to a specific DC/DC circuit topology. Needless to say, when the battery module 111 is discharged, the electric energy thereof is boosted and output through the first DC/DC converter 112; when the battery module 111 is charged, the DC power input to the pack connection terminal 110A is stepped down by the first DC/DC converter 112 to charge the battery module 111. In addition, in the battery cluster 100, each battery pack 110 establishes an electrical connection relationship through the pack connection end 110A and defines the cluster connection end 101, and the specific form is determined by the specific series-parallel structure of each battery pack 110. In this embodiment, the pack connection ends 110A of the battery packs 110 are connected in parallel to a common end, and the common end constitutes the pack connection end 101 of the battery pack 100, so that each battery pack 110 in this embodiment forms a typical parallel output structure, and even if the number of the battery cells 111A included in the battery module 111 of the battery pack 110 is small and the output voltage of the battery pack 110 is low, the discharge performance of the battery pack 100 can be effectively improved, and the uninterruptible power supply application of a power supply system is particularly facilitated.

Referring to fig. 5, the equalizing circuits 113 are respectively connected in series between two adjacent cell units 111A, and each equalizing circuit includes an equalizing resistor 113A and an equalizing switch 113B connected in series.

Referring to fig. 3 and 5, the third BMS management unit 114 acquires external characteristic parameters of each cell unit 111A, including voltage, current, and temperature of the battery pack 110, and performs voltage equalization management on each cell unit 111A, and thus the third BMS management unit 114 further includes corresponding sensors, which will not be described in detail herein. Specifically, the third BMS management unit 114 turns on and off the balancing switch 113B of the corresponding balancing circuit 113 according to the voltage of each battery cell unit 111A to balance the voltage of the corresponding battery cell unit 111A, so that the life of each battery cell unit 111A can be effectively prolonged.

Referring to fig. 2 to 3, the second BMS management unit 120 is in signal connection with the third BMS management unit 114 of each battery pack 110 of the battery cluster 100 where the second BMS management unit 120 is located to determine whether each battery pack 110 is abnormal according to the external characteristic parameters of the cell units 111A of each battery pack 110, and it can be understood that the second BMS management unit 120 determines that the corresponding battery pack 110 is abnormal or failed when the battery pack 110 is under overvoltage, overcurrent, or overtemperature. In addition, the second BMS management unit 120 calculates the SOC and/or SOH of each battery pack 110 according to the external characteristic parameters of the cell unit 111A of each battery pack 110, and provides data support for charging and discharging control, battery life evaluation, and the like of the battery pack 110.

Further, the second BMS management unit 120 also receives a cluster output target for controlling the electrical output parameter of each battery pack 110, which is issued by the first BMS management unit 300, which will be described later. In this embodiment, the cluster output target is a cluster output power set value, so that the second BMS management unit 120 may adjust the output power of each battery pack 110 by adjusting the output current and the output voltage of each battery pack 110, and a specific control loop may be a voltage-current dual closed-loop control or the like, which is not particularly limited in this embodiment. Specifically, the second BMS management unit 120 cuts off all the battery packs 110 within the corresponding battery cluster 100 when the cluster output target is zero, thereby withdrawing the battery cluster 100 from the power output from the side of the battery cluster 100. The second BMS management unit 120 cuts off the abnormal battery pack 110 within the corresponding battery cluster 100 when the cluster output target is not zero, and PWM-modulates the first DC/DC converters 112 within the other battery packs 110 according to the cluster output target to adjust the output power of the corresponding battery cluster 100 by adjusting the output voltage and the output current of the corresponding battery pack 110. In other words, the second BMS controlling unit may control whether the battery pack 110 supplies power for output by using the switch of the first DC/DC converter 112, and does not need to set a dedicated charging/discharging control switch, thereby reducing the number of switches required to be set in the battery pack 110, improving the utilization rate of the switches, reducing the cost of the battery pack 110, and further being suitable for capacity expansion of the power supply system.

Referring to fig. 1, the access unit 200 is configured to access each battery cluster 100, and includes a plurality of cluster access switches (not shown) connected to the cluster connection terminals 101 of each battery cluster 100, and each cluster access switch may be a corresponding relay or contactor. It is understood that the access unit 200 may be a physical power distribution device, such as a junction box, so that the dc power output by each battery cluster 100 can be distributed through the access unit 200 and connected to other current transformation devices, so that the dc power of each battery cluster 100 can be transformed into other forms of power and then output, thereby expanding the application scenarios of each battery cluster 100. As previously described, the access unit 200 may be accessed by an inverter device 400 (shown in fig. 6) such that each battery cluster 100 is electrically coupled to the inverter device 400 to at least discharge thereto. In particular, the converter 400 may be a part of the UPS power system excluding the conventional storage battery, that is, a part including rectification, inversion, and boosting, and its specific structure will be described in detail below, so that when each battery cluster 100 is connected to the converter 400 through the connection unit 200, the power supply system substantially constitutes the UPS power supply system to provide uninterrupted power supply for the load. It should be noted that the access unit 200 should not be construed as a physical power distribution device, and in fact, each cluster access switch included in the access unit 200 may be located inside each battery cluster 100, or inside the corresponding converter device.

Referring to fig. 1, the first BMS management unit 300 signals the second BMS management units 120 of the respective battery clusters 100 to acquire abnormality information of the respective battery packs 110 in the respective battery clusters 100, turns on and off corresponding cluster access switches according to the abnormality information, and transmits the corresponding cluster output targets to the second BMS management units 120 of the respective battery clusters 100. Specifically, in the present embodiment, the first BMS management unit 300 determines the degree of abnormality of each battery cluster 100 according to the number of abnormal battery packs 110 in the battery cluster 100, for example, 10 battery packs 110 are included in the battery cluster 100, and when 10 battery packs 110 are all abnormal, the degree of abnormality is 10; when all 3 battery packs 110 are abnormal, the abnormal degree is 3; when all the battery packs 110 are normal, the degree of abnormality is 0. In this way, the first BMS managing unit 300 may allocate and transmit a reasonable cluster output target corresponding to the degree of abnormality of each battery cluster 100 to each battery cluster 100 in association with the degree of abnormality and the current system output target, thereby achieving the full use of each battery pack 110. Wherein, the current system output target is sent to the first BMS management unit 300 by the upper computer according to the actual operation condition of the system.

In this embodiment, the first BMS management unit 300 turns off the cluster access switch corresponding to the battery cluster 100 when all the battery packs 110 in the battery cluster 100 are abnormal, and allocates and transmits the cluster output target having a value of zero to the corresponding second BMS management unit 120. The first BMS management unit 300 keeps turning on the cluster access switch corresponding to the battery cluster 100 when the non-abnormal battery pack 110 exists in the battery cluster 100, and allocates and transmits the cluster output target having a value not zero to the corresponding second BMS management unit 120.

Preferably, the first BMS managing unit 300 allocates and transmits the cluster output target, the value of which is not zero, to each battery cluster 100 maintaining the access unit 200 according to a weighting rule. In other words, the cluster output target of the battery cluster 100 with a high storage amount of abnormal battery packs 110 is low, and the cluster output target of the battery cluster 100 with a high storage amount of non-abnormal battery packs 110 is high, so that rapid deterioration of the partial battery packs 110 on a uniform basis can be prevented, and the battery packs 110 can be maintained to have substantially the same life.

As can be seen from the above description of the power supply system, the power supply system includes a plurality of battery clusters 100, the battery cluster 100 includes a plurality of battery packs 110, each battery pack 110 includes a first DC/DC converter 112, and the first DC/DC converter 112 is coupled to the battery module 111 to convert and output the output voltage of the battery module 111, so that the capacity of the power supply system using the battery packs 110 and the battery clusters 100 is not required to be expanded by greatly increasing the output voltage of the battery module 111. In other words, under the condition that the battery module 111 outputs a lower voltage, the battery pack 110 can still maintain a certain output voltage during operation to meet the requirement of the power supply system; when maintenance is required, since the output voltage of the battery module 111 is not high, maintenance operation of the battery pack 110 can be performed relatively safely. Therefore, the above structure effectively improves the personnel safety of the battery pack 110 during maintenance and operation, so that the corresponding power supply system is suitable for capacity expansion without worrying about the personnel safety.

In addition, the power supply system according to the embodiment of the present invention further adopts a three-level BMS management architecture based on the above, and the three-level BMS management units (114, 120, 300) are respectively located at a battery pack level, a battery cluster level and a power supply system level, and face the cell unit 111A, the battery pack 110 and the battery cluster 100 to perform corresponding BMS management, so that the power supply system is further convenient for capacity expansion due to other advantages.

Specifically, because the third BMS management unit 114 for acquiring the external characteristic parameters of each cell unit 111A is arranged in the battery pack 110, the second BMS management unit 120 can acquire the external characteristic parameters of each cell unit 111A only by communicating with each third BMS management unit 114 to determine whether each battery pack 110 is abnormal, so that the second BMS management unit 120 does not need to be connected to each cell unit 111A through a large number of wire harnesses, the connection relationship of signal lines in the battery cluster 100 is simple and is not prone to error, and because the signal lines are short, the situations of signal interference and time delay can be effectively improved, the management of the battery cluster 100 is facilitated, and capacity expansion is facilitated.

Furthermore, the power supply system according to the embodiment of the present invention employs a three-level BMS management architecture that communicates with each other, each level BMS manages a sub-battery level according to information reported by the sub-battery level BMS management units, for example, the third BMS management unit 114 is located at a battery pack level and can be used for managing each cell unit 111A, the second BMS management unit 120 is located at a battery cluster level and is used for managing each battery pack 110, and the first BMS management unit 300 is located at a power supply system level and is used for managing each battery cluster 100, so that a situation that a certain battery level automatically cuts off output after detecting that a certain degree of self-fault exists, and further, a large output pressure is generated to other parts of the same battery level does not occur.

In the embodiment of the present invention, the second BMS management unit 120 uploads the abnormal information of the battery packs 110 in the corresponding battery clusters 100 to the first BMS management unit 300, so that the first BMS management unit 300 can accurately acquire the abnormal information of the battery packs 110 in the battery clusters 100 and perform global control on the battery clusters 100 according to the abnormal information, wherein the abnormal information includes whether each battery cluster 100 is accessed and power output, and a cluster output target that each battery cluster 100 accessed and power output needs to achieve; next, the second BMS managing unit 120 receiving the cluster output target may control the electrical output parameters of the battery packs 110 still suitable for power output in the battery cluster 100, so that the battery packs 110 are commonly matched and the battery cluster 100 achieves the above cluster output target, thereby fully utilizing all available battery packs 110 in the power supply system, effectively achieving the operation purpose of the whole system, and improving the stability of the power supply system. In other words, the three-level BMS management architecture of the power supply system respectively adopts an upward reporting mechanism and a downward management mechanism at the communication level and the control level and effectively combines the two mechanisms, thereby solving the defect that the battery pack 110 is not fully utilized in the capacity expansion of the power supply system, and enabling the power supply system to be suitable for capacity expansion.

It can also be seen that, since the battery sections in the power supply system are well-arranged, the battery pack 110, the battery cluster 100 and the whole power supply system have corresponding levels of BMS management units, so that the respective sections are respectively configured in a modular manner, and the battery sections of the whole power supply system are well managed.

With continued reference to fig. 6, the present embodiment also has the following preferred configuration on the basis of the above. It should be noted that only one battery cluster 100 is shown in fig. 6, and each level of BMS management unit and the access unit 200 are not shown in fig. 6.

The access unit 200 has a first end connected to each of the battery clusters 100 and a second end connected to the first end through a corresponding cluster access switch.

The power supply system further comprises the aforementioned converter device 400, wherein the converter device 400 has a battery end 401 and comprises a direct current bus, a second DC/DC converter 430 and a second DC/DC control unit. The battery terminal 401 is connected to the second terminal of the access unit 200 to connect the battery clusters 100, so that the dc power of each battery cluster 100 can be introduced and converted into a wider application. The second DC/DC converter 430 is a bidirectional DC/DC converter, and two sides of the second DC/DC converter are respectively connected to the DC bus and the battery end 401 to realize voltage conversion therebetween, so that each battery cluster 100 is connected to the battery end 401 of the converter 400 instead of the DC bus, and the existing converter 400 does not need to be modified, thereby providing good versatility. In this embodiment, the second DC/DC control unit is configured to control the second DC/DC converter 430 to keep on.

The battery cluster 100 further comprises a first voltage collector 130 for collecting the voltage of its cluster connection terminal 101. Each of the battery packs 110 includes a first DC/DC control unit for controlling an operation direction of a corresponding first DC/DC converter 112. Each first DC/DC control unit is in signal connection with the first voltage collector 130 and controls the corresponding first DC/DC converter 112 to operate in a discharging direction (i.e., operate in a boost mode) when the voltage at the cluster connection end 101 is lower than a first threshold value, so that the corresponding battery module 111 discharges to the inverter 400; when the voltage of the cluster connection end 101 is higher than a second threshold value, each of the first DC/DC control units controls the corresponding first DC/DC converter 112 to operate in a charging direction (i.e., operate in a step-down mode), so that the corresponding battery module 111 is charged by the converter device 400. Wherein the first threshold is less than or equal to a second threshold.

In this embodiment, the first threshold and the second threshold have a certain difference to provide a certain buffer space. In addition, the first DC/DC control unit includes a plurality of first DC/DC controllers 112A corresponding to the first DC/DC converters 112, and each of the first DC/DC controllers 112A is connected to the first voltage collector 130 to obtain the voltage of the cluster connecting end 101, and is used to control the working direction of the corresponding first DC/DC converter 112. Specifically, each of the first DC/DC controllers 112A controls the working direction of the corresponding first DC/DC converter 112 by modulating the duty ratio of the PWM signal, and is applicable to most DC/DC converters, and has a wide application range and a mature technology. Since it is a prior art approach to control a DC/DC converter using PWM modulation, the present invention does not specifically describe the specific processes and principles thereof.

On the basis that the battery pack 110 is correspondingly additionally provided with the bidirectional DC/DC converters, the embodiment of the present invention further provides a first DC/DC control unit, which can control the working direction of each first DC/DC converter 112 and match the operation requirement of the inverter 400 only by simply comparing the voltage of the cluster connection end 101 with the preset threshold. In particular, the reason for this is that each cell cluster 100 is electrically coupled to the converter 400 to discharge or charge it, and each cell cluster 100 is connected to the converter 400 through the cluster connection terminal 101, so that the operation requirement of the converter 400 can be mapped to the voltage of the cluster connection terminal 101, and the control unit can obtain the operation requirement of the converter 400 and perform corresponding control action to match the operation requirement only according to the voltage of the cluster connection terminal 101. In this embodiment, the "operation requirement of the inverter 400" specifically includes two situations: one is that the converter 400 is short of supply and needs the cooperation of the battery clusters 100 to supply power together; secondly, the converter 400 supplies surplus power, and power supply is not needed to be supplied by all the battery clusters 100 together.

In other words, the control of the first DC/DC converter 112 in each battery pack 110 can be independent of the control of the inverter 400, and it is not necessary to establish a direct communication connection with the inverter 400 through an industrial control bus and provide a complex control algorithm, so that each battery pack 110 can be matched with the operation requirement of the power supply system, which is particularly suitable for reducing the complexity of the communication layer and the control layer when the battery pack 110 is in practical use, and reducing the difficulty of field wiring, so that the capacity of the power supply system is easy to expand when the battery pack 110 is large in number.

Moreover, the power supply system according to the embodiment of the present invention further performs a key configuration on the converter device 400, that is, the second DC/DC control unit controls the second DC/DC converter 430 to be kept on when the converter operates, so that the DC bus voltage suitable for reflecting the operation requirement of the converter device 400 can be transmitted to the cluster connection end 101 of each battery cluster 100 through the second DC/DC converter 430, it is ensured that each battery cluster 100 can obtain an effective cluster connection end 101 voltage capable of mapping the operation requirement of the converter device 400 at any time, and the first DC/DC control unit effectively controls the first DC/DC converter 112 to match the operation requirement of the converter device 400, thereby ensuring smooth operation of the power supply system.

Correspondingly, the converter device 400 further includes a second voltage collector 450, configured to collect a voltage of the dc bus. The second DC/DC control unit is a second DC/DC controller 440, which is connected to the second voltage collector 450 to obtain the DC bus voltage. The second DC/DC controller 440 controls the second DC/DC converter 430 to operate in the discharging direction when the DC bus voltage is lower than a third threshold; the second DC/DC controller 440 controls the second DC/DC converter 430 to operate in the charging direction when the DC bus voltage is higher than a fourth threshold. Wherein the third threshold is less than or equal to a fourth threshold. In this embodiment, the third threshold and the fourth threshold have a certain difference. Therefore, the working direction of the second DC/DC converter 430 is controlled by collecting the DC bus voltage, and the stability is high.

It should be noted that, in the term system of the present invention, the "charging direction" and the "discharging direction" both refer to the battery module 111, that is, for any DC/DC converter, the "charging direction" refers to the direction of the electric energy flowing from the current transformer 400 to the battery cluster 100, and conversely, the "discharging direction" refers to the direction of the electric energy flowing from the battery cluster 100 to the current transformer 400.

Specifically, as described above, the inverter 400 of the present embodiment is the UPS system except for the conventional battery, that is, the inverter 400 further includes an AC/DC converter 410 and a DC/AC converter 420. The DC sides of the AC/DC converter 410 and the DC/AC converter 420 are both connected to the DC bus, the AC side of the AC/DC converter 410 is connected to an AC power source, and the AC side of the DC/AC converter 420 outputs an AC power. The high-voltage side of the second DC/DC converter 430 is connected to the DC bus, and the low-voltage side thereof is connected to the battery terminal 401. In this embodiment, the ac power supply is commercial power. Since the conversion processes such as rectification and inversion in the UPS system are prior art, the present invention does not describe them in detail.

The description of the above specification and examples is intended to be illustrative of the scope of the present invention and is not intended to be limiting. Modifications, equivalents and other improvements which may occur to those skilled in the art and which may be made to the embodiments of the invention or portions thereof through a reasonable analysis, inference or limited experimentation, in light of the common general knowledge, the common general knowledge in the art and/or the prior art, are intended to be within the scope of the invention.

Claims

1. A power supply system, comprising: the system comprises a plurality of battery clusters, an access unit and a first BMS management unit;

the battery cluster has a cluster connection end and includes a plurality of battery packs connected to each other, and a second BMS management unit;

the battery pack includes a battery module, a first DC/DC converter, and a third BMS management unit; the battery module comprises a plurality of battery cell units which are connected in series; the low-voltage side of the first DC/DC converter is connected with the battery module, and the high-voltage side of the first DC/DC converter forms a pack connecting end of the battery pack and is used for realizing voltage conversion between the battery module and the pack connecting end; the third BMS management unit is used for acquiring external characteristic parameters of each battery cell unit; wherein, each battery pack establishes an electrical connection relationship through the pack connection end and defines the cluster connection end;

the second BMS management unit is in signal connection with a third BMS management unit of each battery pack of the battery cluster where the second BMS management unit is located so as to judge whether each battery pack is abnormal or not according to the external characteristic parameters of the cell unit of each battery pack; the second BMS management unit further receiving a cluster of output targets to control an electrical output parameter of each battery pack;

the access unit is used for accessing each battery cluster and comprises a plurality of cluster access switches correspondingly connected with the cluster connecting ends of each battery cluster;

and the first BMS management unit is in signal connection with the second BMS management units of the battery clusters to acquire the abnormal information of the battery packs in the battery clusters, and opens and closes the corresponding cluster access switches according to the abnormal information and sends the corresponding cluster output targets to the second BMS management units of the battery clusters.

2. The power supply system of claim 1, wherein: the pack connection ends of the battery packs are connected in parallel to each other to a common end, which constitutes a pack connection end of the battery pack.

3. The power supply system of claim 2, wherein: the cluster output target is a cluster output power given value;

the second BMS managing unit cutting off all the battery packs in the corresponding battery cluster when the cluster output target is zero;

the second BMS managing unit cuts off the abnormal battery pack in the corresponding battery cluster when the cluster output target is not zero, and PWM-modulates the first DC/DC converters in the other battery packs according to the cluster output target to adjust the output power of the corresponding battery cluster by adjusting the output voltage and the output current of the corresponding battery pack.

4. The power supply system of claim 3, wherein:

the first BMS management unit determines the abnormal degree of each battery cluster according to the number of the abnormal battery packs in each battery cluster, and distributes and sends a corresponding cluster output target to each battery cluster by combining the abnormal degree and the current system output target;

the first BMS management unit closes a cluster access switch corresponding to the battery cluster when all battery packs in the battery cluster are abnormal, and allocates and sends the cluster output target with a value of zero to a corresponding second BMS management unit;

and the first BMS management unit keeps turning on a cluster access switch corresponding to the battery cluster when a non-abnormal battery pack exists in the battery cluster, and allocates and sends the cluster output target with a value not equal to zero to a corresponding second BMS management unit.

5. The power supply system of claim 4, wherein: and the first BMS management unit distributes and sends the cluster output targets with the values not equal to zero to each battery cluster which is kept to be accessed to the access unit according to a weighting principle.

6. The power supply system of claim 2, wherein: the battery pack also comprises a plurality of equalizing circuits, each equalizing circuit is connected between two adjacent battery cell units in series and comprises an equalizing resistor and an equalizing switch which are connected with each other in series;

the external characteristic parameters comprise voltages of the battery cell units, and the third BMS management unit further opens and closes corresponding equalization switches according to the voltages of the battery cell units so as to perform voltage equalization on the corresponding battery cell units.

7. The power supply system of claim 2, wherein: the external characteristic parameters comprise voltage, current and temperature;

and the second BMS management unit also calculates the SOC and/or SOH of each battery pack according to the external characteristic parameters of the battery cell unit of each battery pack.

8. The power supply system according to any one of claims 2 to 7, wherein: the maximum output voltage of each battery module is lower than 65V; the number of the battery cell units in each battery module is the same, and each battery cell unit is composed of two single lithium batteries which are connected in parallel.

9. The power supply system according to any one of claims 2 to 7, wherein:

the access unit is provided with a first end and a second end, the first end of the access unit is connected with each battery cluster, and the second end of the access unit is connected with the first end through a corresponding cluster access switch;

the first DC/DC converter in each battery pack is a bidirectional DC/DC converter;

the power supply system further comprises an inverter device, wherein the inverter device is provided with a battery end and comprises a direct current bus, a second DC/DC converter and a second DC/DC control unit; the battery end is connected with the second end of the access unit so as to be connected with each battery cluster; the second DC/DC converter is a bidirectional DC/DC converter, and two sides of the second DC/DC converter are respectively connected with the direct current bus and the battery end and used for realizing voltage conversion between the direct current bus and the battery end; the second DC/DC control unit is used for controlling the second DC/DC converter to be kept on;

the battery cluster also comprises a first voltage collector which is used for collecting the voltage of the cluster connecting end; each of the battery packs includes a first DC/DC control unit for controlling an operation direction of a corresponding first DC/DC converter; each first DC/DC control unit is in signal connection with the first voltage collector and controls the corresponding first DC/DC converter to work in the discharging direction when the voltage of the cluster connecting end is lower than a first threshold value, so that the corresponding battery module discharges to the converter device; when the voltage of the cluster connecting end is higher than a second threshold value, each first DC/DC control unit controls the corresponding first DC/DC converter to work in the charging direction so as to enable the corresponding battery module to be charged by the converter device; wherein the first threshold is less than or equal to a second threshold;

the converter device also comprises a second voltage collector for collecting the voltage of the direct current bus; the second DC/DC control unit is connected with the second voltage collector to obtain the voltage of the direct current bus; the second DC/DC control unit controls the second DC/DC converter to work in a discharging direction when the voltage of the direct current bus is lower than a third threshold; the second DC/DC control unit controls the second DC/DC converter to work in a charging direction when the voltage of the direct current bus is higher than a fourth threshold value; wherein the third threshold is less than or equal to a fourth threshold.

10. The power supply system of claim 9, wherein: the converter device also comprises an AC/DC converter and a DC/AC converter;

the direct current sides of the AC/DC converter and the DC/AC converter are both connected with the direct current bus, the alternating current side of the AC/DC converter is connected with an alternating current power supply, and the alternating current side of the DC/AC converter outputs alternating current;

the high-voltage side of the second DC/DC converter is connected with the direct-current bus, and the low-voltage side of the second DC/DC converter is connected with the battery end.