Pre-charge loop configuration with maximum energy utilization

Abstract

The invention relates to the technical field of energy storage charging safety, in particular to energy utilization maximized pre-charging loop configuration which comprises a battery pack and a high-voltage box bus, the high-voltage box bus comprises a pre-charging relay K4, a high-voltage box main positive relay K1, a pre-charging capacitor C1 and a high-voltage box main negative relay K2, the d1 end of the pre-charging relay K4 is connected with the b2 end of the pre-charging capacitor C1, and the d2 end of the pre-charging capacitor C1 is connected with the b2 end of the high-voltage box main positive relay K1. The high-voltage box bus further comprises a pre-charging relay K3 and a pre-charging resistor R1, and compared with a traditional pre-charging loop combination of a pre-charging relay and a pre-charging resistor, the time for current to pass through the pre-charging resistor is shortened, so that the heating value of the pre-charging resistor is reduced, the energy loss of an energy storage system is reduced, and the energy storage efficiency is improved. Other devices in the high-voltage box are prevented from being influenced by high temperature; in addition, by controlling the charging and discharging relation between the battery clusters and the pre-charging capacitor, the influence generated by inter-cluster ring current can be reduced to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the field of energy storage charging safety technology, and in particular to a pre-charging circuit configuration that maximizes energy utilization. Background Art

[0002] With the continuous development of the energy storage industry, energy storage integrated systems are accelerating towards maximizing energy density, and the demand for single high-energy battery packs is becoming increasingly prominent. However, due to the different internal resistances of lithium-ion batteries, when high-energy, high-voltage battery packs are combined in series and parallel, the charge and discharge imbalance aggravates the current imbalance between batteries during the charging and discharging process, thereby causing inter-cluster circulation.

[0003] At present, the main solution to this problem is to add a pre-charging circuit. The traditional pre-charging circuit solution consists of a pre-charging resistor and a pre-charging relay. However, the existence of the pre-charging resistor in this solution, on the one hand, during the charging process according to Q = I2 Rt, the resistor will generate a lot of heat, which is easy to cause damage to components; at the same time, it further causes a large amount of electrical energy to be converted into heat energy. The longer the pre-charging time, the more electrical energy is wasted. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies of the prior art, the present invention provides a pre-charging circuit configuration that maximizes energy utilization.

[0006] (II) Technical solution

[0007] To achieve the above-mentioned object, the present invention provides the following technical solutions: a pre-charging circuit configuration for maximizing energy utilization, comprising a battery pack and a high-voltage box busbar, wherein the high-voltage box busbar comprises a pre-charging relay K4, a high-voltage box main positive relay K1, a pre-charging capacitor C1 and a high-voltage box main negative relay K2, wherein the d1 end of the pre-charging relay K4 is connected to the b2 end of the pre-charging capacitor C1, the d2 end of the pre-charging relay K4 is connected to the d1 end of the high-voltage box main positive relay K1, and the b1 end of the pre-charging capacitor C1 is connected to the d1 end of the high-voltage box main negative relay K2;

[0008] The high-voltage box busbar further includes a pre-charging relay K3 and a pre-charging resistor R1, wherein the d1 end of the pre-charging relay K3 is connected to the d1 end of the main positive relay K1 of the high-voltage box, the d2 end of the pre-charging relay K3 is connected to the a1 end of the pre-charging resistor R1, and the a2 end of the pre-charging resistor R1 is connected to the d2 end of the main positive relay K1 of the high-voltage box;

[0009] The positive electrode of the battery pack is connected to the d2 terminal of the pre-charge relay K4, and the negative electrode of the battery pack is connected to the b1 terminal of the pre-charge capacitor C1;

[0010] The battery pack and the high-voltage box busbar are arranged in several groups;

[0011] A plurality of battery groups are connected in series.

[0012] (III) Beneficial effects

[0013] Compared with the prior art, the present invention provides a pre-charging circuit configuration that maximizes energy utilization, and has the following beneficial effects:

[0014] Compared with the traditional pre-charging circuit combination of "pre-charging relay + pre-charging resistor", this energy-maximizing pre-charging circuit configuration reduces the time that current passes through the pre-charging resistor, thereby reducing the heat generated by the pre-charging resistor, reducing the energy loss of the energy storage system, and protecting the other components inside the high-voltage box from high temperature. In addition, by controlling the charge and discharge relationship between the battery cluster and the pre-charging capacitor, the impact of inter-cluster circulation can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structural system of the present invention; DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 , a pre-charge circuit configuration for maximizing energy utilization, comprising a battery pack and a high-voltage box busbar, wherein the high-voltage box busbar comprises a pre-charge relay K4, a high-voltage box main positive relay K1, a pre-charge capacitor C1 and a high-voltage box main negative relay K2, wherein the d1 end of the pre-charge relay K4 is connected to the b2 end of the pre-charge capacitor C1, the d2 end of the pre-charge relay K4 is connected to the d1 end of the high-voltage box main positive relay K1, and the b1 end of the pre-charge capacitor C1 is connected to the d1 end of the high-voltage box main negative relay K2;

[0018] The high-voltage box busbar further includes a pre-charging relay K3 and a pre-charging resistor R1, wherein the d1 end of the pre-charging relay K3 is connected to the d1 end of the main positive relay K1 of the high-voltage box, the d2 end of the pre-charging relay K3 is connected to the a1 end of the pre-charging resistor R1, and the a2 end of the pre-charging resistor R1 is connected to the d2 end of the main positive relay K1 of the high-voltage box;

[0019] The d1 end of the pre-charge relay K4 is connected to the b2 end of the pre-charge capacitor C1, and the d2 end of K4 is connected to the d1 end of the main positive relay K1 of the high-voltage box; the b1 end of the pre-charge capacitor C1 is connected to the d1 end of the main negative relay K2 of the high-voltage box, which is equivalent to C1 and K4 being connected in series and then connected in parallel between the two ends of the high-voltage box busbar. This circuit is called circuit 1;

[0020] The d1 end of the pre-charge relay K3 is connected to the d1 end of the main positive relay K1 of the high-voltage box, and the d2 end of K3 is connected to the a1 end of the pre-charge resistor R1; the a2 end of the pre-charge resistor R1 is connected to the d2 end of the main positive relay K1 of the high-voltage box, which is equivalent to K3 and R1 being connected in series and then connected in parallel between the positive busbars of the high-voltage box. This circuit is called circuit 2;

[0021] The positive electrode of the battery pack is connected to the d2 terminal of the pre-charge relay K4, and the negative electrode of the battery pack is connected to the b1 terminal of the pre-charge capacitor C1;

[0022] The battery pack and the high-voltage box busbar are arranged in several groups;

[0023] A plurality of battery groups are connected in series.

[0024] When the battery system is ready to start discharging (the battery system and the load side have not yet formed a loop, and the main positive / negative relay at the high-voltage box bus terminal has not yet been closed), the BMS completes the power-on self-test and manually closes the high-voltage box main circuit breaker. At this time, the BMS makes the first voltage difference judgment between the battery clusters:

[0025] 1. If the voltage difference between clusters is less than 10V, a. close the main negative relay K2; b. close the pre-charge relay K3 of loop 2, and use the pre-charge resistor R1 to limit the current to prevent the voltage across the capacitive components in the loop from changing suddenly (the terminal voltage is 0) at the moment of power-on, causing a large current in the loop and impacting the device; c. disconnect K3 after loop 2 is turned on for 2s, and close the pre-charge relay K4 of loop 1 at the same time. When the current passes through the pre-charge capacitor C1, the capacitor will store unbalanced energy between clusters; d. close the main positive relay K1 after loop 1 is turned on for 3s, and disconnect K4 after another 2s. At this time, the power-on is completed.

[0026] 2. If the voltage difference between clusters is ≥10V and <20V, a. close the main negative relay K2; b. close the pre-charge relay K3 of loop 2;

[0027] c. After loop 2 is turned on for 2s, disconnect K3 and close the pre-charge relay K4 of loop 1 at the same time; d. At this time, after the BMS pressure difference detection is less than 10V, repeat the c~d steps in judgment ①.

[0028] 3. If the voltage difference between clusters is ≥20V, the BMS alarm prompts power-on failure. At this time, grid connection is prohibited and manual maintenance is required.

[0029] After the first inter-cluster voltage difference is balanced, energy is stored in the pre-charge capacitor C1. When the system is shut down and restarted for voltage difference balance next time, the BMS calculates the average voltage of each cluster. If the voltage difference between the cluster voltage and the system average voltage is less than 2V, the pre-charge capacitors C1, C2...Cn are enabled to charge the cluster battery; if the voltage difference between the cluster voltage and the system average voltage is greater than 2V: a. If the voltage difference is greater than 2V and less than 10V, repeat steps a to d in judgment ①; b. If the voltage difference is greater than 10V and less than 20V, repeat steps a to d in judgment ②.

[0030] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0031] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0032] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A pre-charging circuit configuration for maximizing energy utilization, comprising a battery pack and a high-voltage box bus, characterized in that: The high-voltage box busbar includes a pre-charge relay K4, a high-voltage box main positive relay K1, a pre-charge capacitor C1 and a high-voltage box main negative relay K2, the d1 end of the pre-charge relay K4 is connected to the b2 end of the pre-charge capacitor C1, the d2 end of the pre-charge relay K4 is connected to the d1 end of the high-voltage box main positive relay K1, and the b1 end of the pre-charge capacitor C1 is connected to the d1 end of the high-voltage box main negative relay K2; The high-voltage box busbar further includes a pre-charging relay K3 and a pre-charging resistor R1, wherein the d1 end of the pre-charging relay K3 is connected to the d1 end of the main positive relay K1 of the high-voltage box, the d2 end of the pre-charging relay K3 is connected to the a1 end of the pre-charging resistor R1, and the a2 end of the pre-charging resistor R1 is connected to the d2 end of the main positive relay K1 of the high-voltage box; The positive electrode of the battery pack is connected to the d2 terminal of the pre-charge relay K4, and the negative electrode of the battery pack is connected to the b1 terminal of the pre-charge capacitor C1; The battery pack and the high-voltage box busbar are arranged in several groups; A plurality of battery groups are connected in series.

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