Battery unit, energy storage system and battery unit fault protection method

Abstract

The invention discloses a battery unit, an energy storage system and a battery unit fault protection method so as to realize battery unit level fault protection. The battery unit comprises a battery cell part, a battery monitoring unit, a first controllable switch and a second controllable switch, the first controllable switch is a single-time irreversible switch; a battery monitoring unit in the battery unit is used for triggering a first controllable switch in the battery unit to be switched off when the battery unit is detected to have a fault, so that the battery unit is connected with other battery units in series to form an open circuit; and the second controllable switch in the battery unit is triggered to be closed, so that the battery unit is bypassed, and the battery unit without faults in the circuit can continue to work.

Description

[0001] This application is a divisional application of the application with the application number 202110592706.1, the application date of May 28, 2021, and the invention title of "A Battery Cell, an Energy Storage System and a Method for Protecting Battery Cell Faults". Technical Field

[0002] The present invention relates to the technical field of energy storage, and more specifically, to a battery cell, an energy storage system and a method for protecting battery cell faults. Background Art

[0003] Regarding a single battery or a combination of multiple single batteries as a battery cell, and then connecting multiple battery cells in series to meet the energy storage voltage boosting and capacity expansion requirements. During the charging and discharging process of the series circuit of battery cells, if an individual battery cell fails, it is necessary to perform fault protection in a timely manner to avoid further expansion of the situation. Summary of the Invention

[0004] In view of this, the present invention provides a battery cell, an energy storage system and a method for protecting battery cell faults to achieve fault protection at the battery cell level.

[0005] A battery cell includes a battery core part, a battery monitoring unit, a first controllable switch and a second controllable switch; the first controllable switch is a single-use irreversible switch.

[0006] The battery monitoring unit in the battery cell is configured to, when detecting a fault in this battery cell: trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells; and trigger the second controllable switch in this battery cell to close, thereby bypassing this battery cell to ensure that the battery cells without faults in the circuit can continue to work.

[0007] Optionally, the battery monitoring unit in the battery cell is configured to, when detecting a fault in this battery cell, first trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells, and then trigger the second controllable switch in this battery cell to close while keeping the first controllable switch in this battery cell open, thereby bypassing this battery cell to ensure that the battery cells without faults in the circuit can continue to work.

[0008] Optionally, the fault includes any one or any combination of over-temperature, over-voltage, under-voltage and over-current.

[0009] Optionally, the battery monitoring unit in the battery cell acquires the operating parameters of this battery cell and determines whether this battery cell is faulty based on this.

[0010] Alternatively, the battery monitoring unit within the battery cell acquires the operating parameters of this battery cell and uploads them to the battery management unit for centralized control of all battery cells in the circuit. The battery management unit determines whether this battery cell is faulty and sends the determination result to the battery monitoring unit in this battery cell.

[0011] Optionally, the first controllable switch within the battery cell is connected in series on either the positive side or the negative side of this battery cell. The battery cell part of this battery cell is connected in series with the first controllable switch within this battery cell and then connected in parallel with the second controllable switch within this battery cell.

[0012] Optionally, the single - use irreversible switch is an active fuse.

[0013] Optionally, the second controllable switch is a repeatable reversible switch.

[0014] Optionally, the repeatable reversible switch is a DC contactor, a DC relay, a DC circuit breaker, an IGBT, or a MOSFET.

[0015] Optionally, the battery cell part is a single battery cell, or a series combination of multiple battery cells, or a parallel combination of multiple battery cells, or a series - parallel combination of multiple battery cells.

[0016] An energy storage system includes a circuit formed by connecting in series a plurality of battery cells of any one of the above - disclosed types.

[0017] Optionally, the energy storage system further includes: a power conversion device connected to the rear stage of the circuit; the power conversion device is still capable of performing charge - discharge operations on the battery cells when the number of battery cells connected in series in the circuit decreases.

[0018] A method for protecting a battery cell from faults, the battery cell including a battery cell part, a battery monitoring unit, a first controllable switch, and a second controllable switch; the first controllable switch is a single - use irreversible switch;

[0019] The method includes:

[0020] The battery monitoring unit within the battery cell detects whether this battery cell has a fault;

[0021] If so, trigger the first controllable switch within this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells; and trigger the second controllable switch within this battery cell to close, thereby bypassing this battery cell, ensuring that the battery cells without faults in the circuit can continue to operate.

[0022] Optionally, trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells; and trigger the second controllable switch in this battery cell to close, thereby bypassing this battery cell, ensuring that the battery cells without faults in the circuit can continue to work. Specifically, it includes: first trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells, and then trigger the second controllable switch in this battery cell to close while keeping the first controllable switch in this battery cell open, thereby bypassing this battery cell, ensuring that the battery cells without faults in the circuit can continue to work.

[0023] Optionally, the battery monitoring unit in the battery cell detects whether this battery cell has a fault, including: the battery monitoring unit in the battery cell obtains the operating parameters of this battery cell, and accordingly judges whether this battery cell has a fault.

[0024] Alternatively, the battery monitoring unit in the battery cell detects whether this battery cell has a fault, including:

[0025] The battery monitoring unit in the battery cell obtains the operating parameters of this battery cell and uploads them to the battery management unit for centralized control of all battery cells in the circuit;

[0026] The battery management unit judges whether this battery cell has a fault and sends the judgment result to the battery monitoring unit in this battery cell.

[0027] As can be seen from the above technical solutions, when any battery cell in the battery cell series circuit of the present invention fails, the battery cell series circuit is opened and the faulty battery cell is bypassed. Thus, on the premise of not affecting the normal operation of the battery cells without faults, the fault protection at the battery cell level, the repair and replacement of the faulty battery cell can be completed, avoiding the further expansion of the situation. Moreover, the selection of the single - use irreversible switch avoids the mis - adhesion after the first controllable switch is opened, achieving reliable disconnection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a schematic structural diagram of a battery cell disclosed in an embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the installation position of a first controllable switch disclosed in an embodiment of the present invention;

[0031] Figure 3 Another schematic diagram of the installation position of a first controllable switch disclosed in an embodiment of the present invention;

[0032] Figure 4 Another schematic diagram of the installation position of a first controllable switch disclosed in an embodiment of the present invention;

[0033] Figure 5 Schematic diagram of the disconnection process of an active fuse disclosed in an embodiment of the present invention;

[0034] Figure 6 Flowchart of a battery cell fault protection method disclosed in an embodiment of the present invention;

[0035] Figure 7 is Figure 6 Flowchart of the specific implementation method of the method shown. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Refer to Figure 1 , an embodiment of the present invention discloses a battery cell, including a battery core part, a battery monitoring unit, a first controllable switch K1 and a second controllable switch K2;

[0038] The first controllable switch is a single - use irreversible switch;

[0039] The battery monitoring unit in the battery cell is used for, when detecting a fault in this battery cell: triggering the first controllable switch K1 in this battery cell to disconnect, thereby opening the circuit formed by connecting this battery cell in series with other battery cells (i.e., the battery cell series circuit where this battery cell is located); and triggering the second controllable switch K2 in this battery cell to close, thereby bypassing this battery cell to ensure that the battery cells without faults in the battery cell series circuit can continue to work.

[0040] Figure 1 Only take "each battery cell in the battery cell series circuit has the same structure, the battery core part of the battery cell is composed of multiple single - cell batteries connected in series, and the first controllable switch K1 is connected in series on the positive - electrode side of the battery cell" as an example. Next, based on this example, the working principle of the embodiment of the present invention will be described in detail:

[0041] Initially, the first controllable switch K1 in each battery cell is in the closed state, and the second controllable switch K2 in each battery cell is in the open state. At this time, all battery cells in the entire series circuit of battery cells are in the working state. The battery monitoring unit in each battery cell collects the operating parameters of this battery cell in real time. The operating parameters include but are not limited to parameters such as the cell temperature, cell voltage, and cell current of this battery cell. Then, the battery monitoring unit in each battery cell independently determines whether this battery cell is faulty based on the operating parameters, or sends it to the battery management unit for centralized control of all battery cells, and then the battery management unit determines whether this battery cell is faulty. If an individual battery cell fails, the battery monitoring unit triggers the first controllable switch K1 in this faulty battery cell to open. At this time, the entire series circuit of battery cells is open, and the entire series circuit of battery cells stops working, avoiding further expansion of the situation. The battery monitoring unit also triggers the second controllable switch K2 in this faulty battery cell to close. At this time, this faulty battery cell is bypassed, and the battery cells without faults in the entire series circuit of battery cells re-establish an electrical circuit and continue to charge and discharge. In this way, it is possible to complete the fault protection at the battery cell level, the repair and replacement of faulty battery cells without affecting the normal operation of the battery cells without faults. After the faulty battery cell is replaced, the second controllable switch K2 in the new battery cell is in the default open state.

[0042] Optionally, from the perspective of maximizing the avoidance of further expansion of the situation caused by faulty battery cells and improving the circuit safety, the preferred triggering order of the first controllable switch K1 and the second controllable switch K2 in the embodiments of the present invention is: first disconnect the first controllable switch K1, and then close the second controllable switch K2. That is to say: the battery monitoring unit in the battery cell is used to, when detecting that this battery cell fails, first trigger the first controllable switch K1 in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells (that is, the series circuit of battery cells where this battery cell is located), and then trigger the second controllable switch K2 in this battery cell to close while keeping the first controllable switch K1 in this battery cell open, thereby bypassing this battery cell and ensuring that the battery cells without faults in the series circuit of battery cells can continue to work.

[0043] In addition, it should be noted that in other examples, for the first controllable switch K1 in any battery cell, the first controllable switch K1 can also be connected in series on the negative electrode side of this battery cell (as Figure 2 shown), or the first controllable switch K1 can also be connected in series between any two single cells in the middle of this battery cell (as Figure 3As shown in the figure; when the battery unit is composed of multiple single cells connected in series first and then in parallel, a first controllable switch K1 can also be provided between any two single cells in the middle of each single cell series branch (as Figure 4 shown). In short, the number and installation position of the first controllable switch K1 are reasonably set according to actual needs, as long as the entire battery unit series circuit can be opened. For reasons such as convenient installation and saving the number of switches used, the embodiment of the present invention recommends connecting the first controllable switch K1 in series on the positive side or the negative side of the battery unit. The cell part of this battery unit is connected in series with the first controllable switch K1 in this battery unit and then in parallel with the second controllable switch K2 in this battery unit.

[0044] The battery management unit can be integrated into the power conversion device connected to the rear stage of the battery unit series circuit, or can be set independently, without limitation.

[0045] The cell part of the battery unit is not limited to the series combination of multiple single cells, and may also include only one single cell, or may also be a parallel combination or a series-parallel combination of multiple single cells.

[0046] The battery unit in the embodiment of the present invention can be a battery pack commonly known in the industry, and the battery unit series circuit can be a battery cluster commonly known in the industry.

[0047] The so-called single-use irreversible switch refers to a switch that forms a mechanical break point after being disconnected and cannot be reconnected. In the embodiment of the present invention, the first controllable switch is set as a single-use irreversible switch, which avoids accidental adhesion after the first controllable switch is disconnected and realizes reliable disconnection.

[0048] The single-use irreversible switch is, for example, an active fuse. During normal operation, the active fuse is equivalent to a current-carrying body such as a copper bar or an aluminum bar, and its internal resistance is much smaller than that of a traditional passive fuse, and it operates faster than a traditional passive fuse. Optionally, the active fuse includes an igniter, a piston, and a current-carrying body (such as a copper sheet), etc. When the single-use irreversible switch receives a turn-off trigger signal, the igniter is ignited, and the igniter burns to generate gas. Under the action of the gas pressure, the piston presses down to break the current-carrying body, forming a mechanical break point and cutting off the electrical circuit, as Figure 5 shown.

[0049] From the above description, it can be seen that in the embodiment of the present invention, when any battery unit in the battery unit series circuit fails, the battery unit series circuit is opened, and the faulty battery unit is bypassed, so that the battery unit-level fault protection, repair, and replacement of the faulty battery unit can be completed without affecting the normal operation of the non-faulty battery units, and the situation can be prevented from further expanding. Moreover, the selection of the single-use irreversible switch avoids accidental adhesion after the first controllable switch is disconnected and realizes reliable disconnection.

[0050] Optionally, to avoid repeatedly and frequently replacing the second controllable switch K2, the second controllable switch K2 is preferably a repeatable reversible switch. A repeatable reversible switch refers to a switch that can be repeatedly turned on and off.

[0051] The repeatable reversible switch can be a DC contactor, a DC relay, a DC circuit breaker, an IGBT, a MOSFET, etc. After it is turned off, it will cut off the electrical circuit by forming an electrical break point and can be restored.

[0052] In addition, an embodiment of the present invention also discloses an energy storage system, including: a circuit formed by connecting in series a plurality of battery units of any one of the above-disclosed types.

[0053] Optionally, the energy storage system further includes a power conversion device connected to the rear stage of the circuit.

[0054] Among them, the power conversion device allows wide voltage access, that is, even when the number of series-connected battery units decreases, it still has the ability to charge and discharge the battery units, and the repair of a faulty battery unit does not affect the normal operation of the power conversion device. The power conversion device can be, for example, a two-stage energy storage converter, the front stage of which is a DC / DC unit and the rear stage of which is a DC / AC unit.

[0055] Corresponding to the above battery unit embodiment, an embodiment of the present invention also discloses a method for protecting a battery unit from failure. The battery unit includes a battery cell part, a battery monitoring unit, a first controllable switch, and a second controllable switch; the first controllable switch is a single-use irreversible switch; as Figure 6 shown, the method includes:

[0056] Step S01: The battery monitoring unit in the battery unit detects whether the battery unit has a failure; if so, go to step S02; if not, return to step S01;

[0057] Among them, the step S01 can specifically be: the battery monitoring unit in the battery unit obtains the operating parameters of the battery unit and determines whether the battery unit has a failure based on this. Alternatively, the S01 can also be: the battery monitoring unit in the battery unit obtains the operating parameters of the battery unit, uploads them to a battery management unit for centralized control of all battery units in the circuit, the battery management unit determines whether the battery unit has a failure, and sends the determination result to the battery monitoring unit in this battery unit.

[0058] Among them, the operating parameters include but are not limited to parameters such as the cell temperature, cell voltage, and cell current of this battery unit. The failure includes any one or any combination of over-temperature, over-voltage, under-voltage, and over-current.

[0059] Step S02: Trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells; and trigger the second controllable switch in this battery cell to close, thereby bypassing this battery cell to ensure that the battery cells without faults in the circuit can continue to operate.

[0060] Optionally, referring to Figure 7 , step S02 can be specifically refined into the following steps S021 to S022:

[0061] Step S021: Trigger the first controllable switch in this battery cell to open, thereby opening the circuit formed by connecting this battery cell in series with other battery cells; then enter step S03;

[0062] Step S022: While keeping the first controllable switch in this battery cell open, trigger the second controllable switch in this battery cell to close, thereby bypassing this battery cell to ensure that the battery cells without faults in the circuit can continue to operate.

[0063] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the methods disclosed in the embodiments, since they correspond to the battery cells disclosed in the embodiments, the descriptions are relatively simple. For the relevant parts, refer to the descriptions of the battery cell part.

[0064] The terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar different objects, and do not necessarily need to describe a specific order or sequence. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. Without further limitations, the element defined by the statement "including one" does not exclude the existence of another identical element in the process, method, commodity or device including the element.

[0065] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the embodiments of the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery cell, comprising a cell part, characterized in that, it further comprises a battery monitoring unit, a first controllable switch and a second controllable switch; the first controllable switch is a single - use irreversible switch, and the single - use irreversible switch is a switch that forms a mechanical break point after being disconnected and cannot re - establish a connection; the second controllable switch is a repeatable reversible switch, and the repeatable reversible switch is a switch that can be repeatedly turned on and off; the cell part is a single battery, or a series combination of multiple single batteries, or a parallel combination of multiple single batteries, or a series - parallel combination of multiple single batteries; both the first controllable switch and the second controllable switch are controlled by the battery monitoring unit; the battery monitoring unit in the battery cell is configured to, when detecting a fault in this battery cell: trigger the first controllable switch in this battery cell to disconnect, thereby opening the circuit formed by this battery cell in series with other battery cells; and trigger the second controllable switch in this battery cell to close; wherein, the battery monitoring unit in the battery cell acquires the operating parameters of this battery cell, uploads them to a battery management unit for centralized control of all battery cells in the circuit, and the battery management unit determines whether this battery cell is faulty and sends the determination result to the battery monitoring unit in this battery cell.

2. The battery cell according to claim 1, characterized in that, the battery monitoring unit in the battery cell is configured to, when detecting a fault in this battery cell, first trigger the first controllable switch in this battery cell to disconnect, thereby opening the circuit formed by this battery cell in series with other battery cells, and then trigger the second controllable switch in this battery cell to close while keeping the first controllable switch in this battery cell disconnected, thereby bypassing this battery cell to ensure that the battery cells without faults in the circuit can continue to work.

3. The battery cell according to claim 1 or 2, characterized in that, the fault includes any one or a combination of any multiple of over - temperature, over - voltage, under - voltage and over - current.

4. The battery cell according to claim 1 or 2, characterized in that, the first controllable switch in the battery cell is connected in series on the positive - electrode side or the negative - electrode side of this battery cell, and after the cell part of this battery cell is connected in series with the first controllable switch in this battery cell, it is then connected in parallel with the second controllable switch in this battery cell.

5. The battery cell according to claim 1 or 2, characterized in that, the single - use irreversible switch is an active fuse.

6. The battery cell according to claim 1 or 2, characterized in that, the repeatable reversible switch is a DC contactor, a DC relay, a DC circuit breaker, an IGBT or a MOSFET.

7. An energy storage system, characterized in that, it comprises: a circuit formed by connecting multiple battery cells as described in any one of claims 1 - 6 in series.

8. The energy storage system according to claim 7, characterized in that, the energy storage system further comprises: a power conversion device connected to the rear - stage of the circuit; The power conversion device is still capable of charging and discharging the battery cells even when the number of battery cells connected in series in the circuit is reduced.

9. A method for protecting battery cells from failure, where the battery cells include a cell part, characterized in that, the battery cells further include a battery monitoring unit, a first controllable switch, and a second controllable switch; the first controllable switch is a single-use irreversible switch, which is a switch that forms a mechanical break point after being disconnected and cannot re-establish a connection; the second controllable switch is a repeatable reversible switch, which is a switch that can be repeatedly turned on and off; the cell part is a single battery cell, or a series combination of multiple single battery cells, or a parallel combination of multiple single battery cells, or a series-parallel combination of multiple single battery cells; the first controllable switch and the second controllable switch are both controlled by the battery monitoring unit; the method includes: the battery monitoring unit in the battery cells detects whether a failure occurs in the battery cells; if so, the battery monitoring unit triggers the first controllable switch in the battery cells to disconnect, thereby opening the circuit formed by connecting the battery cells in series with other battery cells; and triggers the second controllable switch in the battery cells to close; wherein, the battery monitoring unit in the battery cells detecting whether a failure occurs in the battery cells includes: the battery monitoring unit in the battery cells obtains the operating parameters of the battery cells and uploads them to a battery management unit for centralized control of all battery cells in the circuit; the battery management unit determines whether the battery cells are faulty and sends the determination result to the battery monitoring unit in the battery cells.

10. The method for protecting battery cells from failure according to claim 9, characterized in that, triggering the first controllable switch in the battery cells to disconnect, thereby opening the circuit formed by connecting the battery cells in series with other battery cells; and triggering the second controllable switch in the battery cells to close, thereby bypassing the battery cells, to ensure that the battery cells without failure in the circuit can continue to work, specifically includes: first triggering the first controllable switch in the battery cells to disconnect, thereby opening the circuit formed by connecting the battery cells in series with other battery cells, and then triggering the second controllable switch in the battery cells to close while keeping the first controllable switch in the battery cells disconnected, thereby bypassing the battery cells, to ensure that the battery cells without failure in the circuit can continue to work.

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