Energy storage system with over-charge and over-discharge protection function

Abstract

The technical scheme of the utility model discloses an energy storage system with an over-charge and over-discharge protection function, which comprises a high-voltage box and N battery packs which form a loop with the high-voltage box and are connected in series, N is greater than or equal to 2, and the energy storage system is characterized in that the nth battery pack comprises a battery and an excitation fuse which is connected with the battery in series, n = 1,..., N. According to the utility model, risks and defects existing in an energy storage system (especially a lithium iron phosphate energy storage system), especially in the aspect of main loop protection, can be solved. According to the utility model, by introducing the excitation fuse, the self-excitation protection action of fault current is realized, and an external signal trigger protection function is realized, so that the safety and the reliability of a system are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of energy storage systems. BACKGROUND

[0002] The safe operation of energy storage systems plays a crucial role in maintaining power supply stability, promoting the effective integration of renewable energy, reducing overall energy costs, protecting personal and equipment safety, and driving environmental protection and sustainable development. Given the importance of energy storage systems, strengthening safety supervision and technical research and development of energy storage systems to ensure the safety and reliability of energy storage systems in various application scenarios is an important task currently facing.

[0003] However, the safe operation of energy storage systems faces challenges from various harmful factors, which can come from internal systems, external environments, and operation management. Among them, overcharging and over-discharging are two major safety hazards. When overcharging occurs in the energy storage system, the voltage inside the battery will rise rapidly, while the current may decrease. This rapid rise in voltage can cause abnormal reactions of chemical materials inside the battery, leading to battery swelling, liquid leakage, and even explosion. In contrast to overcharging, when over-discharging occurs in the energy storage system, the voltage of the battery decreases, and the change in current may not be obvious. Continuous over-discharging can lead to a decrease in active materials inside the battery, a decrease in battery performance, and even a battery short circuit or damage.

[0004] Currently, the protection of overcharging and over-discharging in energy storage systems is mainly achieved through the battery management system (BMS). BMS can monitor real-time parameters such as battery voltage, current, and temperature, and control the charging and discharging of the battery according to preset thresholds to prevent overcharging and over-discharging. However, the BMS management system also has certain risks and deficiencies:

[0005] (1) Risk of BMS system failure: If the BMS management system itself fails or fails, it may not accurately monitor and control the charging and discharging state of the battery, increasing the risk of overcharging and over-discharging in the energy storage system.

[0006] (2) Risk of poor battery performance consistency: In the energy storage system, due to differences in production process, materials, and use environment of the battery, the performance of different batteries may differ greatly. This performance difference can make it difficult for the BMS system to accurately match the control of charging and discharging, increasing the risk of overcharging or over-discharging.

[0007] (3) External environmental factors: The operating environment of the energy storage system may affect the performance of the BMS system. For example, high temperature, humidity, corrosion and other environmental factors may cause the hardware devices of the BMS system to malfunction or degrade in performance. These environmental factors may also affect the chemical reaction rate and internal pressure of the battery, increasing the risk of overcharging or overdischarging.

[0008] (4) Insufficient maintenance and management: The safe operation of the energy storage system requires regular maintenance and management, including cleaning, inspection and repair of the hardware devices of the BMS system, and performance testing and replacement of the battery. If the maintenance and management are insufficient, it may lead to the degradation of the performance of the BMS system and the battery, thereby increasing the risk of overcharging or overdischarging.

[0009] (5) Technical update challenge: With the continuous development of energy storage technology, the BMS management system also needs to be updated and upgraded to adapt to new battery types and charging and discharging strategies. However, this update and upgrade may bring additional costs and complexity. Utility model content

[0010] The technical problem to be solved by the utility model is that the BMS management system still has certain risks and deficiencies in the overcharge and overdischarge protection of the energy storage system.

[0011] In order to solve the above technical problems, the technical scheme of the utility model is to disclose an energy storage system with overcharge and overdischarge protection function, comprising a high voltage box and N battery packs in series connected with the high voltage box to form a loop, N≥2, characterized in that the nth battery pack comprises a battery and an excitation fuse connected in series with the battery, n=1,…,N.

[0012] Preferably, the high voltage box comprises a positive electrode loop and a negative electrode loop connected with the N battery packs in series to form a loop, at least one fuse is arranged on the positive electrode loop and / or the negative electrode loop, and the fuse is an excitation fuse or a non-excitation fuse.

[0013] Preferably, M fuses are arranged on the positive electrode loop and / or the negative electrode loop of the high voltage box, M≥2, and at least m excitation fuses are arranged in the M fuses, m≥1.

[0014] Preferably, one fuse is arranged on the positive electrode loop and the negative electrode loop of the high voltage box respectively, and one of the two fuses is an excitation fuse and the other is a non-excitation fuse.

[0015] Preferably, the structure of the excitation fuse used in the battery pack is the same as or different from that of the excitation fuse used in the high voltage box.

[0016] Preferably, the excitation fuse comprises a current sampling device connected in series to the positive pole of the DC bus of the energy storage system, a first igniter connected to the current sampling device, and a second igniter for receiving an external signal.

[0017] Preferably, the current sampling device is a fuse or a current sensor.

[0018] Preferably, the second igniter is connected to the BMS system.

[0019] Preferably, the excitation fuse further comprises a voltage sampling and judging module, a positive input terminal of which is connected to the positive pole of the DC bus of the energy storage system, a negative input terminal of which is connected to the negative pole of the DC bus of the energy storage system, and a signal output terminal of which is connected to the second igniter.

[0020] Preferably, the voltage sampling and judging module comprises a voltage detecting unit and a control unit.

[0021] A positive input terminal of the voltage detecting unit is connected to the positive pole of the DC bus of the energy storage system, a negative input terminal of the voltage detecting unit is connected to the negative pole of the DC bus of the energy storage system, and a signal output terminal of the voltage detecting unit is connected to a signal input terminal of the control unit.

[0022] A signal output terminal of the control unit is connected to the second igniter.

[0023] The utility model can solve the risk and the deficiency existing in the energy storage system (especially the lithium iron phosphate energy storage system), especially in the main loop protection. The utility model discloses the excitation fuse, realizes the self-excitation protection action to the fault current, and has the external signal trigger protection function, thereby improves the safety and the reliability of system. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The schematic diagram of the energy storage system with overcharge and overdischarge protection function disclosed in the embodiment;

[0025] Figure 2 The principle schematic diagram of the excitation fuse used in embodiment 1;

[0026] Figure 3 The principle schematic diagram of the excitation fuse used in embodiment 2. DETAILED DESCRIPTION

[0027] The utility model will be further described in combination with specific embodiments. It should be understood that these embodiments are only used for illustrating the utility model and are not used for limiting the scope of the utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0028] Embodiment 1

[0029] As Figure 1 shown, the utility model discloses a kind of overcharge overdischarge protection function's energy storage system is to apply incentive fuse in each battery pack PACK and high voltage box BPU.

[0030] The working principle of traditional fuse (i.e. non-incentive fuse such as aR or aBat class fuse) is based on current overload protection, i.e. when the current exceeds the specified value of the fuse, the fuse inside the fuse will melt due to heat, thereby cutting off the circuit and playing a protective role. However, since the current change is not significant during overcharge and overdischarge (such as current may decrease during overcharge, and current change is not obvious during overdischarge), the traditional fuse cannot effectively protect the overcharge and overdischarge of the energy storage system.

[0031] The embodiment adopts an incentive fuse with only current sampling function as Figure 2 shown, mainly composed of pressure sensor, signal fuse 1 (as a current sampling device, the current sampling device can also be a Hall sensor, at this time, the Hall sensor needs to be connected with a control unit), ignition tube 2, 3, arc extinguishing fuse 4, etc. Among them, the ignition tube is divided into two: the first ignition tube 2 is connected in parallel across the signal fuse 1, for triggering action after the signal fuse 1 is fused; the second ignition tube 3 can be directly connected with external signal through the terminal, for receiving external trigger signal. Figure 2 The incentive fuse with the structure as Figure 2 shown has only short-circuit protection function, in order to make the entire system disclosed in the embodiment have overcharge and overdischarge protection function, the second ignition tube 3 is connected with the existing BMS system through the terminal, and cooperates with the BMS system to realize overcharge and overdischarge protection function. The internal trigger circuit of the incentive fuse as Figure 2 shown is completely isolated from external trigger signal, and does not affect each other, so as to realize active and passive integration. The working principle of the incentive fuse is similar to the fuse device in weapon. When system fault current appears, the signal fuse 1 is fused first, the voltage across the two ends becomes large and is loaded across the two ends of the first ignition tube 2, the first ignition tube 2 is triggered to act, explosion impact is generated, mechanical rod is pushed to move, Busbar is quickly cut off, and rapid cutting of the circuit is realized. At the same time, the second ignition tube 3 can receive external signal, and when the external signal meets the trigger condition, ignition action can also be performed, and the circuit is cut off. It should be noted that the utility model does not involve improvement of the incentive fuse.

[0032] In the technical solution disclosed in this embodiment, an excitation fuse is provided in each battery pack (eight battery packs in this embodiment, namely PACK1 to PACK8) of the energy storage system. The excitation fuse is integrated in the MSD (manual disconnect device). The MSD can be regarded as a mounting base for installing the excitation fuse, which is a conventional structure well known to those skilled in the art and will not be described in detail here. The excitation fuse set in the battery pack is mainly used to realize short circuit protection and overcharge protection.

[0033] Furthermore, in the technical solution disclosed in this embodiment, the positive circuit of the high-voltage box BPU uses a conventional fuse FU1, and its negative circuit uses an activated fuse FU2. It should be noted that fuses can be installed only in the positive circuit of the high-voltage box BPU, or only in the negative circuit of the high-voltage box BPU. The fuses used can be activated fuses or conventional fuses. Multiple fuses can also be installed in the positive circuit of the high-voltage box BPU, and / or multiple fuses can be installed in the negative circuit of the high-voltage box BPU. Among all the fuses installed in the positive and / or negative circuits, one fuse is an activated fuse, and the others are conventional fuses. These solutions are all feasible. Figure 1 Only the optimal solution for the high-voltage box BPU is shown.

[0034] exist Figure 1 In the technical solution shown, the conventional fuse FU1 and the excitation fuse FU2 are respectively matched with contactor KM2 and contactor KM3, and connected to switch QS, thereby realizing full-range protection of the DC system. Figure 1 In this circuit, KM1 is a pre-charge relay. When the energy storage system is powered on, the pre-charge relay KM1 closes, and the excitation current is limited by the large resistor R connected in series with the pre-charge relay KM1. After the energy storage system stabilizes, the pre-charge relay KM1 opens.

[0035] When any battery pack within the battery cluster is short-circuited, the excitation fuse of the short-circuited battery pack will trip, cutting off the faulty circuit.

[0036] When the battery cluster is short-circuited externally, the conventional fuse FU1 in the high-voltage box BPU blows quickly, while the excitation fuse FU2 does not activate.

[0037] When overcharge or over-discharge faults occur in the system, the Battery Management System (BMS) first attempts to disconnect the main circuit. If the BMS fails, the excitation fuse FU2 will trip. If FU2 fails, the excitation fuse within the battery pack will trip, cutting off the faulty circuit and achieving system protection.

[0038] In the technical solution disclosed in this utility model, the arc-front I of the excitation fuse is adjusted. 2T is matched with contactors KM2 and KM3 to prevent contactors from sticking together in the event of a system fault. Here, I represents the fusing current, and T represents the fusing time. It should be noted that, according to common knowledge in the art, adjusting the arc-precession I of the excitation fuse... 2 There are various methods for T, which are accomplished by the manufacturers of the excitation fuses, and will not be elaborated here.

[0039] After the trigger fuse trips, only the main busbar needs to be replaced. Compared to the traditional fuse which requires the entire circuit to be replaced, the maintenance and replacement costs are lower and more environmentally friendly. This reduces the system's operation and maintenance costs and is conducive to sustainable environmental development.

[0040] Example 2

[0041] like Figure 3 As shown, the energy storage system with overcharge and over-discharge protection disclosed in this embodiment differs from Embodiment 1 in that the excitation fuse used has both current sampling and voltage sampling functions. In addition to the signal fuse 1, ignition tubes 2 and 3, and arc-extinguishing fuse 4, the excitation fuse in this embodiment also includes a voltage detection circuit. The voltage detection circuit is a conventional circuit well-known to those skilled in the art; for example, a sampling resistor can be used, which will not be elaborated here. Due to the addition of the voltage sampling function, the excitation fuse in this embodiment has both short-circuit protection and overcharge and over-discharge protection functions. In this case, it is no longer necessary to connect the second ignition tube 3 to the BMS system; instead, the second ignition tube 3 is connected to the control unit. The control unit receives the voltage sampling signal given by the voltage detection circuit, thereby realizing the overcharge and over-discharge protection function. It should be noted that... Figure 3 The signal fuse 1 in the circuit can also be replaced by a Hall sensor. The control unit receives the current sampling signal from the Hall sensor, thereby realizing the short-circuit protection function. For example... Figure 3 As shown, one end of the voltage detection circuit is connected to the positive terminal of the DC bus of the energy storage system, and the other end is connected to the negative terminal of the DC bus. Figure 3 It indicated Figure 1 The structure of any one of the battery packs. Figure 1 The excitation fuse FU2 in the middle can also be adopted as follows: Figure 3 The excitation fuse shown is based on a similar principle, and therefore no further drawings are provided here. The other structures and working principles of this embodiment are similar to those of Embodiment 1, and will not be described in detail here.

Claims

1. An energy storage system with overcharge and overdischarge protection function, comprising a high-voltage box and N battery packs in series with the high-voltage box forming a loop, N≥2, characterized in that, The nth battery pack comprises a battery and an excitation fuse connected in series with the battery, n=1,…,N; the high-voltage box comprises a positive loop and a negative loop formed by the N series-connected battery packs, at least one fuse is arranged on the positive loop and / or the negative loop, and the fuse is an excitation fuse or a non-excitation fuse.

2. The energy storage system having overcharge and overdischarge protection function according to claim 1, wherein, M fuses are arranged on the positive loop and / or the negative loop of the high-voltage box, M≥2, and at least m excitation fuses are included in the M fuses, m≥1.

3. The energy storage system having overcharge and overdischarge protection function according to claim 1, wherein, One excitation fuse and one non-excitation fuse are arranged on the positive loop and the negative loop of the high-voltage box respectively.

4. The energy storage system having overcharge and overdischarge protection function according to claim 1, wherein, The excitation fuse used by the battery pack is the same as or different from the excitation fuse used by the high-voltage box.

5. The energy storage system having overcharge and overdischarge protection function according to claim 4, wherein, The excitation fuse comprises a current sampling device connected in series with the positive DC bus of the energy storage system, a first ignition tube connected with the current sampling device, and a second ignition tube for receiving an external signal.

6. The energy storage system having overcharge and overdischarge protection function according to claim 5, wherein, The current sampling device is a fuse or a current sensor.

7. The energy storage system having overcharge and overdischarge protection function according to claim 5, wherein, The second ignition tube is connected with a BMS system.

8. The energy storage system having overcharge and overdischarge protection function according to claim 5, wherein, The excitation fuse further comprises a voltage sampling and judgment module, a positive input end of the voltage sampling and judgment module is connected with the positive DC bus of the energy storage system, a negative input end of the voltage sampling and judgment module is connected with the negative DC bus of the energy storage system, and a signal output end of the voltage sampling and judgment module is connected with the second ignition tube.

9. The energy storage system having overcharge and overdischarge protection function according to claim 8, wherein, The voltage sampling and judgment module comprises a voltage detection unit and a control unit, a positive input end of the voltage detection unit is connected with the positive DC bus of the energy storage system, a negative input end of the voltage detection unit is connected with the negative DC bus of the energy storage system, a signal output end of the voltage detection unit is connected with a signal input end of the control unit, and a signal output end of the control unit is connected with the second ignition tube.

Images