Battery set and battery system

Abstract

Provided are a storage battery set and a storage battery system which have superior redundancy to failures of a single cell. In the present invention, a module battery has at least one string formed by series-connecting a large number of single cells which are secondary batteries of a high-temperature operating type. The large number of single cells constituting the at least one string are divided into a plurality of cell groups. The module battery comprises a main path having series-connected thereto the plurality of cell groups, and a bypass path that enables individual bypassing of each of the cell groups in the at least one string. When a failure has occurred in at least one of the large number of single cells, an energizing path is set to be bypassed from the main path to the bypass path at a position of a cell group to which the failed single cell belongs.

Description

[Technical field]

[0001] The present invention relates to a module battery comprising a large number of high-temperature operating secondary batteries connected together, and is particularly directed to the configuration of the current-carrying paths therein. [Background technology]

[0002] Sodium-sulfur batteries (hereinafter referred to as NaS batteries) are already known as storage batteries that are used in connection with a power grid. A single NaS battery (single cell) is a high-temperature operating secondary battery that has a structure in which active materials, metallic sodium (Na) and sulfur (S), are isolated and stored in a cell (battery container) with beta alumina, a solid electrolyte with Na ion conductivity, as a separator. The operating temperature is about 300°C, and in the single cell, electromotive force is generated by the electrochemical reaction of both active materials in a molten (liquid) state at the operating temperature.

[0003] In order to ensure the desired capacity and output, NaS batteries are usually used in the form of a module battery in which multiple cells (battery assembly) are interconnected and housed in a heat-insulated container (see, for example, Patent Document 1). In a module battery, blocks are formed by connecting multiple circuits (strings) in parallel, each of which has multiple cells connected in series, and multiple such blocks are connected in series.

[0004] There is a general need to operate a NaS battery module composed of multiple cells with higher output and for longer periods than before. For example, if this is to be realized in a conventional battery module composed of multiple strings connected in parallel, as disclosed in Patent Document 1, it may seem at first glance that this can be easily achieved by increasing the number of cells that make up the string (the number of direct connections) or the number of blocks.

[0005] However, it may be difficult for a module battery of a conventional configuration such as that disclosed in Patent Document 1 to be adapted to high output for the following reasons.

[0006] First, when a cell belonging to one of the strings in a block fails, all the cells in the string including the failed cell, including the normal ones, will be unused. Therefore, the more cells connected in series in one string, the more normal cells will be unused. This is not desirable from the viewpoint of cell utilization efficiency.

[0007] Furthermore, if a failure of a cell causes no current to flow through a string in that block, the voltage (output) is maintained only by the remaining strings in which all the cells are operating normally (no failed cells). In this case, it goes without saying that in order to maintain the same output as before the failure, it is necessary to increase the magnitude of the current flowing through the cells that make up the remaining strings. In other words, the more strings with failed cells there are, the greater the load on the cells that make up the remaining strings. For example, if a cell failure occurs in two strings in a module battery with 12 strings connected in parallel, the overload ratio of the cells in the remaining strings is 12 / (12-10) = 1.09 times.

[0008] On the other hand, to ensure safety, each string is provided with a fuse so that a current exceeding a preset limit value (for example, 200 A) does not flow through the single cell.

[0009] Therefore, the lifespan of a conventional module battery depends on the number of strings containing failed cells and the limiting current value of the cells, and increasing the output affects both of these factors.

[0010] There is also the idea of ​​increasing the number of parallel strings in advance to suppress the magnitude of the current flowing through each string compared to the limit current value. In this case, however, a problem arises in current design, in that the total current flowing under normal conditions (the sum of the currents flowing through each string) becomes unnecessarily large.

[0011] Moreover, from the viewpoint of cost, it is desirable to realize high output while minimizing the total number of unit cells.

[0012] As a result of extensive research, the inventors of the present invention discovered that increasing redundancy against cell failure, in other words, minimizing the number of cells that become unused due to the failure of a cell and suppressing an increase in current flowing through the cells, is effective in increasing the output of a module battery, and thus arrived at the present invention. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] International Publication No. 2015 / 056739 Summary of the Invention

[0014] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a storage battery set and a storage battery system that have excellent redundancy against failure of a single cell.

[0015] In order to solve the above problems, a first aspect of the present invention is a storage battery set including at least one string in which a large number of unit cells, each of which is a high-temperature operating secondary battery, are connected in series, the large number of unit cells constituting the at least one string are divided into a plurality of cell groups, the storage battery set includes a main path in which the plurality of cell groups are connected in series, and a bypass path capable of individually bypassing each of the plurality of cell groups within the at least one string, a gate switch made of a semiconductor element capable of switching a current-carrying state ON / OFF is provided between cell groups among the plurality of cell groups that are connected in series to each other in the main path, and in a bridge path that connects the upstream and downstream sides of each cell group to the bypass path, and in the plurality of cell groups, one module battery is configured for every two cell groups that are connected in series to each other, and the bypass path is provided for each module battery, and the module battery comprises, as the gate switch, an inter-group gate provided between the two cell groups in the main path, a module end gate provided between the downstream sides of the two cell groups in the main path and another module battery connected to the module battery, four bridge gates connecting the upstream and downstream sides of each of the two cell groups in the main path to the bypass path provided in the module battery, and a terminal bridge gate connecting the most downstream side of the main path to the bypass path provided in the module battery, If at least one of the plurality of single cells fails, By switching the ON / OFF state of the gate switch corresponding to the cell group to which the failed battery belongs, The current path is bypassed from the main path to the bypass path at the cell group to which the failed cell belongs.

[0019] In addition, the present invention 2 The embodiment is 1a storage battery set according to the embodiment, characterized in that each of the module batteries is accommodated in a storage container equipped with a heater and a cooling fan, and in the storage container, single cells belonging to the two cell groups are arranged for each cell group and accommodated in two rows, and a connection portion including the inter-group gate, the module end gate, the four bridge gates, and the terminal bridge gate is provided on one side of the storage container perpendicular to the arrangement direction of the single cells.

[0020] In addition, the present invention 3 The first aspect is or No. 2 attitude Like The storage battery set is characterized in that the plurality of cell groups are each composed of eight single cells.

[0021] In addition, the present invention 4 The first aspect is or No. 2 attitude Like This storage battery set is characterized in that the at least one string is two strings, a first string and a second string, and when the current path is bypassed in the first string, the current paths of the cell groups in the second string are also bypassed in the same number as the number of cell groups bypassed in the first string.

[0022] In addition, the present invention 5 The aspect of the present invention relates to a battery storage system, further comprising an AC-DC converter connected to the at least one string. According to the first or second aspect The power storage system is characterized by comprising a storage battery set and a controller that controls the storage battery set, and the storage battery set is connected to a transformer.

[0023] In addition, the present invention 6 The embodiment is 5The storage battery system according to the above aspect is characterized in that it comprises a plurality of the storage battery sets and a plurality of the controllers each controlling the storage battery set, and the plurality of the storage battery sets are connected in parallel to the transformer.

[0024] The first to third aspects of the present invention 6 According to this aspect, even if a certain cell in the module battery fails, it is possible to continue to supply current to the string including the cell by bypassing at least one cell group including the cell group to which the cell in question belongs. This realizes a module battery with excellent redundancy against cell failure, and further a rechargeable battery system including the module battery.

[0025] In particular, 1 and No. 2 According to this aspect, by suitably determining the ON / OFF state of each gate switch, even if the number of failed single cells increases, the increase in the number of gate switches that become current paths through the bypass can be suppressed, and the effect of voltage drop caused by an increase in the number of gate switches that become current paths due to failure of a single cell can be suitably suppressed.

[0026] In particular, 1 and 2 According to this aspect, when a cell fails, the ON / OFF state of each gate switch is switched on a module battery basis, and does not affect other module batteries belonging to the same string. Also, as long as the increase in the number of gate switches used is suppressed only in the module battery that is the subject of ON / OFF state switching control, the number of gate switches used in the entire string does not increase.

[0027] In particular, 4 According to this aspect, even if a unit cell in one string fails, the electromotive forces in the two strings remain the same, so that redundancy against unit cell failure is more suitably ensured. [Brief description of the drawings]

[0028] [Figure 1] 1 is a diagram showing a schematic configuration of a storage battery system 1. FIG. [Diagram 2] FIG. 2 is a diagram showing a circuit configuration in a part of a string ST. [Diagram 3] 11 is a diagram showing a current flow state in a string ST when no single cell is faulty. FIG. [Figure 4] 11 is a diagram showing an example of a current flow state in a string ST when one cell 5 in the string ST breaks down. FIG. [Diagram 5] FIG. 11 is a diagram showing an example of a current flow state in a string ST when two unit cells 5 housed in the same housing container 11 of the string ST break down. [Figure 6] 2 is a top view illustrating a state in which a cell 5 is housed in a housing container 11. FIG. [Figure 7] 2 is a side view illustrating a state in which a cell 5 is housed in a housing container 11. FIG. [Figure 8] 2 is a side view illustrating a state in which a cell 5 is housed in a housing container 11. FIG. [Figure 9] 1 is a diagram showing a schematic configuration of a module battery housing 100. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] <Battery storage system configuration> 1 is a diagram illustrating a schematic configuration of a storage battery system 1 according to the present embodiment. The storage battery system 1 includes a storage battery set 2 including a plurality of cells 5, each of which is a storage battery, and a controller 3 that controls the storage battery set 2.

[0030] The storage battery set 2 generally includes two strings ST (ST1, ST2) each of which has a plurality of unit cells (also referred to as cells) 5 connected in series. In each string ST, one cell group 10 is formed for each of m (m is a natural number) unit cells 5 (5(1) to 5(m)) connected in series. Furthermore, two cell groups 10 connected in series to each other are accommodated in one storage container 11 to form one module battery 4. FIG. 1 illustrates an example in which n (n is a natural number) module batteries 4 (4(1) to 4(n)) are formed by the unit cells 5 that make up each string ST.

[0031] In other words, in FIG. 1, n×2m=2mn cells 5 are connected in series to form one string ST, and in each string ST, the 2mn cells 5 are divided and housed in n storage containers 11, each containing 2m cells, to form n module batteries 4. The total number of cells in the storage battery set 2 is 2mn×2=4mn. In each of the n module batteries 4, the 2m cells 5 are divided into two cell groups 10. Note that the specific values ​​of m and n in each string ST are the same. A more detailed configuration of the string ST will be described later.

[0032] Each of the cells 5 is a sodium-sulfur battery (NaS battery). More specifically, each of the cells 5 is a high-temperature operating secondary battery that uses metallic sodium (Na) and sulfur (S) as active materials and beta alumina, a solid electrolyte having Na ion conductivity, as a separator that separates the two. Hereinafter, the electromotive force of one cell 5 during discharge is defined as V0.

[0033] Each storage container 11 also includes a heater 11h for heating the cell 5 during standby to keep both active materials in a molten (liquid) state, a fan 11f for cooling the cell 5 that generates heat as a result of the reaction between the two active materials during operation, and a temperature sensor 11t for monitoring (detecting) the temperature inside the storage container 11. Note that, although one heater 11h, one fan 11f, and one temperature sensor 11t are shown in each storage container 11 in Fig. 1, this is merely schematic, and the actual number and arrangement of each of these may be set appropriately.

[0034] The string (first string) ST1 and the string (second string) ST2 are connected in parallel to the DC side of a PCS (AC-DC converter: power conversion system) 13 via a termination unit 12 equipped with a fuse or the like to prevent excessive current from flowing through each of them. The AC side of the PCS 13 is connected to a transformer 14, and the transformer 14 is connected to a system 15 outside the storage battery set 2.

[0035] In this embodiment, for simplicity of explanation, the configuration is assumed in which the storage battery system 1 has only one storage battery set 2, but this is not a required aspect, and the configuration may also be such that multiple storage battery sets 2 are connected in parallel to the transformer 14.

[0036] The controller 3 mainly includes a charge / discharge control unit 31 that controls the charge / discharge operation of the storage battery set 2, and a temperature control unit 32 that controls the temperature of the storage container 11 both during operation and during standby. The controller 3 can be realized by executing a predetermined operation program in a dedicated or general-purpose computer (not shown) equipped with a CPU, memory, storage, etc., and the charge / discharge control unit 31 and the temperature control unit 32 are realized as virtual components in the computer.

[0037] The charge / discharge control unit 31 includes a bypass control unit 31b. The bypass control unit 31b generally has a function of switching a current path in a string ST when any of the cells 5 constituting the string ST fails for some reason, so that the cell group 10 including the failed cell 5 is bypassed.

[0038] The temperature control unit 32 includes a heater control unit 32h and a fan control unit 32f. The heater control unit 32h and the fan control unit 32f respectively control the operation of the heater 11h and the fan 11f in response to an output signal from a temperature sensor 11t provided in the storage container 11. In summary, during standby, the heater control unit 32h controls the on / off of the heating operation of the heater 11h to maintain the temperature of the unit cells 5 in the storage container 11 at a predetermined atmospheric temperature (for example, about 300°C), and during operation, the fan control unit 32f controls the on / off of the air blowing operation of the fan 11f to cool the unit cells 5 that generate heat due to a reaction of the active material.

[0039] <Detailed string configuration> Next, a more detailed configuration of the string ST (ST1, ST2) will be described. Fig. 2 is a diagram showing the circuit configuration of a part of the string ST. Since the two strings ST1 and ST2 provided in the storage battery set 2 have the same configuration, Fig. 2 shows only one string ST.

[0040] More specifically, FIG. 2 shows the connection state in the vicinity of the single cells 5 contained in the storage container 11 constituting the kth (k is a natural number equal to or less than n-1)th module battery 4(k) and the storage container 11 constituting the k+1th module battery 4(k+1) of the string ST.

[0041] In the following description, the path in which the cells 5 are connected in series in each string ST is referred to as a main path La. For convenience, the upward direction of the main path La in the drawing is referred to as the upstream side, and the downward direction is referred to as the downstream side. In each string ST, a current flows toward the downstream side during charging, and a current flows toward the upstream side during discharging.

[0042] As described above, in the string ST, 2m cells 5 divided into two cell groups 10 of m cells each are housed in respective storage containers 11; however, for the sake of simplicity, FIG. 1 illustrates the 2m cells 5 simply connected in series.

[0043] However, in the actual main path La of the string ST, an inter-group gate G1 is provided between two cell groups 10 accommodated in one accommodation vessel 11, as shown in FIG.

[0044] In addition, in each storage vessel 11 of the string ST, a bypass path Lb is provided in addition to the main path La. In terms of the circuit configuration, the bypass path Lb is considered to be provided in parallel with the main path La. Therefore, as with the main path La, the terms "upstream side" and "downstream side" are used for the bypass path Lb according to the up-down direction in the drawing.

[0045] Four bridge paths Lca, Lcb, Lcc, and Lcd are provided to connect the upstream and downstream sides of the two cell groups 10 in the main path La to the bypass path Lb, and each bridge path Lca, Lcb, Lcc, and Lcd is provided with bridge gates G2a, G2b, G2c, and G2d, respectively.

[0046] In addition, in the main path La, a module end gate G3 is provided downstream of the two cell groups 10 accommodated in one storage container 11. In the string ST, the single cells 5 belonging to the cell groups 10 accommodated in different storage containers 11 are also connected in series on the main path La, and the module end gate G3 is provided between the cell groups 10 whose storage containers 11 are different on the main path La. In other words, the module end gate G3 is common to the inter-group gate G1 in that it is provided between the cell groups 10 on the main path La.

[0047] Furthermore, the downstream side of the module end gate G3 in the main path La and the container 11 in the bypass path Lb are connected by a bridge path Lce. The bridge path Lce is provided with a bridge gate G2e. Hereinafter, the bridge gate G2e may be particularly referred to as a terminal bridge gate G2e.

[0048] Although not shown in FIG. 2, the most upstream side of the main path La (the upstream side of the cell group 10 contained in the storage container 11 that constitutes the modular battery 4(1)) and the most downstream side (the downstream side of the cell group 10 contained in the storage container 11 that constitutes the modular battery 4(n)) are connected to the PCS 13.

[0049] The inter-group gate G1, the five bridge gates G2 (G2a, G2b, G2c, G2d, G2e), and the module end gate G3 are gate switches of the same configuration, each including two semiconductor elements (more specifically, MOSFETs) SD. Hereinafter, the state in which a current flows through these gate switches is referred to as the "ON state" or simply "ON," and the state in which a current does not flow is referred to as the "OFF state" or simply "OFF." The ON / OFF states of these gate switches are controlled by the bypass control unit 31b.

[0050] In the storage battery system 1 according to this embodiment, during operation (charging and discharging), the bypass control unit 31b performs bypass control by switching the ON / OFF state of each gate switch depending on the failure status (location and number of failures) of the cells 5 in each string ST included in the storage battery set 2. This makes it possible for the storage battery system 1 to bypass only a selected specific cell group 10 and pass electricity through the string ST.

[0051] <Bypass control in storage battery sets> Hereinafter, the bypass control during operation of the storage battery system 1 and the current supply state achieved thereby will be described in stages according to the degree of failure of the single cell 5.

[0052] In principle, in the storage battery system 1 according to the present embodiment, when a certain cell 5 belonging to a string ST formed by dividing a large number of cells 5 into a plurality of cell groups 10 and connecting them in series fails, a bypass is performed for the cell group 10 including the failed cell 5. In other words, the cell groups 10 that do not include the failed cell 5 but that belong to the same string ST are used as they are even after the failure occurs.

[0053] When a certain cell group 10 is bypassed, the maximum electromotive force in the string ST is reduced by the amount of the cell group 10. However, even in the string ST in which the electromotive force is reduced in this manner, it is possible to obtain the same output as when there is no fault by passing a current larger than that when there is no fault within a preset limit value range. In this case, the overload ratio, which is the ratio of the magnitude of the current flowing through each cell 5 to the magnitude of the current flowing when there is no fault, is expressed as 2mn / (2mn-αm)=2n / (2n-α), where α is the number of faulty cells. The larger the value of the overload ratio, the closer the current flowing through the cell 5 approaches the limit value.

[0054] (When there is no battery failure) Fig. 3 is a diagram showing the current flow in the string ST when there is no failure in the single cell. Specifically, Fig. 3 shows the circuit configuration of a part of the string ST that is the same as Fig. 2, and also shows the ON / OFF states of the gate switches and the current flow paths realized thereby.

[0055] If none of the cells 5 is faulty, the bypass control unit 31b turns all inter-group gates G1 and module end gates G3 in the string ST to the ON state, and turns all bridge gates G2 (G2a, G2b, G2c, G2d, G2e) to the OFF state. As a result, in all of the strings ST, as shown by the arrows AR11 to AR14, current flows only through the main path La, and no current flows through the bypass path Lb or any of the bridge paths. In this case, in the storage battery set 2, the two strings ST1 and ST2, in which 2mn cells 5 are connected in series, are connected in parallel, so that an electromotive force of up to 2mnV0 can be obtained during discharge.

[0056] (When one battery in a string fails) FIG. 4 is a diagram showing an example of a current flow state in a string ST when one of the cells 5 in the string ST breaks down.

[0057] More specifically, for both strings ST1 and ST2, FIG. 4 shows the connection state in the vicinity of the storage container 11 constituting the kth module battery 4(k) and the single battery 5 contained in the storage container 11 constituting the k+1th module battery 4(k+1), as in FIG. 2.

[0058] Now, suppose that a certain cell 5x(1) belonging to a battery module 4(k) of string ST1 fails. When the charge / discharge control unit 31 detects this failure, the bypass control unit 31b switches the inter-group gate G1 and the module end gate G3 in the main path La of the battery module 4(k) to which the failed cell 5x(1) belongs from the ON state to the OFF state, and switches the bridge gate G2b in the bridge path Lcb connected to the upstream side of the inter-group gate G1 and the terminal bridge gate G2e in the bridge path Lce connected to the most downstream side of the battery module 4(k) from the OFF state to the ON state.

[0059] As a result, in the module battery 4(k) of the string ST1, no current flows through the cell group 10 to which the failed cell 5x(1) belongs, or through the inter-group gate G1 and module end gate G3 that sandwich it. Instead, as shown by arrows AR21 to AR24, the current path is bypassed from the main path La to the bridge path Lcb, the bypass path Lb, and the terminal bridge path Lce.

[0060] In the string ST1 excluding the module battery 4(k) containing the failed cell 5, the main path La is maintained as the current path, as shown by arrows AR25 and AR26, for example, in the same way as when there is no failure in the cell 5.

[0061] In the storage battery system 1 according to the present embodiment, when a certain cell 5 fails, the bypass of the cell group 10 including the cell 5 is performed in principle as follows. , G This is achieved by switching the inter-loop gate G1 from the ON state to the OFF state, and switching one bridge gate G2 located on each of the upstream and downstream sides of the cell group 10 that can achieve the intended bypass from the OFF state to the ON state.

[0062] For example, in the case shown in Figure 4 , GIt is also possible to bypass the cell group including the failed cell 5x(1) by switching the inter-loop gate G1 from the ON state to the OFF state and switching the bridge gates G2b and G2d from the OFF state to the ON state. In this case, the number of gate switches constituting the current path increases by one due to the bypass.

[0063] However, since the resistance loss increases as the number of gate switches increases, it is desirable to keep the number of gate switches as small as possible when bypassing.

[0064] In the example shown in Fig. 4, in consideration of this point, in addition to the inter-group gate G1 in the main path La, the module end gate G3 also switches from the ON state to the OFF state, and the gate switch used for bypassing downstream of the cell group 10 to which the failed cell 5x(1) belongs is set to the terminal bridge gate G2e, so that the number of gate switches used remains unchanged before and after bypassing is performed. This prevents an increase in resistance loss due to bypassing.

[0065] Also, although not shown in the figure, if a single battery 5 belonging to another cell group 10 contained in the same storage container 11 fails rather than the cell group 10 to which the single battery 5x(1) belongs, the bypass control unit 31b switches the inter-group gate G1 in the storage container 11(k) of the string ST1 from the ON state to the OFF state, and switches the bridge gate G2a in the bridge path Lca connected upstream of the cell group 10 to which the failed single battery 5 belongs and the bridge gate G2c in the bridge path Lcc connected downstream of the inter-group gate G1 from the OFF state to the ON state.

[0066] In this case, in the battery module 4(k) of the string ST1, no current flows through the cell group 10 to which the failed cell 5 belongs and the inter-group gate G1 located downstream of it, and instead the current path is bypassed from the main path La to the bridge path Lca, the bypass path Lb, and the bridge path Lcc. In this case, the number of gate switches constituting the current path increases by one due to the bypass.

[0067] In any case, when a cell 5 belonging to the string ST1 fails, the maximum electromotive force in the string ST1 will drop by mV0 from the value of 2mnV0 in a state where there is no failed cell 5.

[0068] However, if only the string ST1 is bypassed in this way, the maximum electromotive force in the string ST2 remains at a value of 2mnV0, and the electromotive force in the string ST1 and the electromotive force in the string ST2 connected in parallel thereto will no longer be balanced. Therefore, in the storage battery system 1 according to the present embodiment, when a failure of a cell 5 belonging to a cell group 10 in one of the two strings ST causes a decrease in the maximum electromotive force in that string ST, the same decrease in electromotive force is intentionally caused in the string ST to which the failed cell does not belong.

[0069] Specifically, the gate switch is switched between ON / OFF to prevent current from flowing to any of the cell groups 10, and a bypass of the current path similar to that of the string ST to which the failed cell 5 belongs is also performed in the string ST to which the failed cell 5 does not belong.

[0070] In the case shown in Fig. 4, such bypassing is performed in the module battery 4(k+1) of the string ST2 to which the failed cell 5x(1) does not belong. More specifically, the inter-group gate G1 and module end gate G3 belonging to the module battery 4(k+1) are switched from the ON state to the OFF state, and the bridge gate G2b provided on the bridge path Lcb connected to the upstream side of the inter-group gate G1 and the terminal bridge gate G2e provided on the bridge path Lce are switched from the OFF state to the ON state.

[0071] As a result, in the module battery 4(k+1) of the string ST2, no current flows through the inter-group gate G1 and the cell group 10 located downstream of it. Instead, as shown by arrows AR33 to AR36, the current path is bypassed from the main path La to the bridge path Lcb, the bypass path Lb, and the bridge path Lce.

[0072] In the string ST2 excluding the module battery 4(k+1), the main path La is maintained as the current path, for example, as indicated by arrows AR31 and AR32.

[0073] As a result, the maximum electromotive force in the string ST2 also drops by mV0 from the value 2mnV0, and the maximum electromotive forces in the strings ST1 and ST2 become equal at 2mnV0-mV0=(2n-1)mV0.

[0074] The selection of the cell group 10 to be bypassed in the string ST to which the failed cell 5 does not belong is basically arbitrary. Therefore, the cell group 10 belonging to the module battery 4(k+1) of the string ST2 in Fig. 4 is selected as the bypass target only by way of example, and a cell group 10 included in the same or another storage container 11 may be selected as the bypass target. In that case as well, the cell group 10 and the inter-group gate G1 included in the same storage container 11 are bypassed by two bridge paths and a bypass path Lb.

[0075] However, if it is known in advance from the operating state or the like that there is a cell 5 that is nearing the end of its life, that cell 5 may be preferentially selected as a bypass target.

[0076] As described above, when one of the cells 5 belonging to any of the strings ST fails, the storage battery set 2 continues to be used as a battery with a maximum electromotive force of (2n-1)mV0.

[0077] (When two batteries fail) Next, consider a case where, after one cell 5 fails, another cell 5 fails as shown in Fig. 4. This can occur in the following three cases (i) to (iii).

[0078] [Case (i): When a cell 5 fails in a string ST to which the first failed cell 5 does not belong] In this case, in the string ST to which the newly failed cell 5 belongs, the bypass control unit 31b switches the ON / OFF state of the gate switch so that the cell group 10 including the newly failed cell 5 becomes the target of bypass instead of the cell group 10 that had been selected as the target of bypass to make the maximum electromotive force uniform even though the newly failed cell 5 was not present.

[0079] Therefore, in case (i), there is no change in the storage battery set 2 and it continues to be used as a battery with a maximum electromotive force of (2n-1) mV0.

[0080] [Case (ii): In the string ST to which the first failed cell 5 belongs, a cell 5 belonging to the same module battery 4 as the failed cell 5 also fails] In this case, in the string ST to which the first failed cell 5 belongs, the cell group 10 including the newly failed cell 5 is further bypassed. In addition, in order to make the electromotive forces uniform, any cell group 10 is further bypassed in the string ST to which the failed cell 5 does not belong.

[0081] More specifically, in a string ST to which two failed cells 5 belong, the two cell groups 10 of the module battery 4 to which the two failed cells 5 belong are bypassed together. On the other hand, in a string ST in which no failed cells exist, two cell groups 10 are arbitrarily selected from the entire string ST and bypassed. Note that in this case, the cell group 10 that would have been bypassed if there was only one failed cell 5 may continue to be bypassed, or two new cell groups 10 may be selected and bypassed.

[0082] In either case, in case (ii), the maximum electromotive force in each string ST is further reduced by mV0 from the case where only one failed cell 5 exists. As a result, in case (ii), the storage battery set 2 continues to be used as a battery with a maximum electromotive force of 2(n-1)mV0.

[0083] FIG. 5 is a diagram illustrating an example of a current flow state in a string ST when two single cells 5 housed in the same housing container 11 of a certain string ST fail, illustrating the case (ii).

[0084] More specifically, FIG. 5 shows a situation in which, as shown in FIG. 4, when a single cell 5x(1) belonging to one of the cell groups 10 included in a certain module battery 4(k) of a string ST1 is the first to fail (the first to fail), and then a single cell 5x(2) belonging to the other cell group 10 housed in the same storage container 11 newly fails (the second to fail), causing the two cell groups 10 to be bypassed.

[0085] Furthermore, Figure 5 also shows a situation in which, even in a string ST2 in which a faulty battery 5 is not present, the other cell group 10 included in the same module battery 4(k+1) as the cell group 10 that was bypassed when there was only one faulty battery 5 as shown in Figure 4 is further bypassed, resulting in two cell groups 10 contained in one storage container being bypassed.

[0086] First, regarding the string ST1, as a result of the charge / discharge control unit 31 detecting a new failure of the single battery 5x(2), the bypass control unit 31b switches the bridge gate G2a provided in the bridge path Lca connected upstream of the cell group 10 to which the failed single battery 5x(2) belongs from the OFF state to the ON state, while again switching the bridge gate G2b provided in the bridge path Lcb, which had been in the ON state for bypassing since the failure of the single battery 5x(1), from the ON state to the OFF state.

[0087] As a result, in the module battery 4(k) of the string ST1, no current flows through the cell group 10 to which the failed cell 5x(1) and cell 5x(2) belong and the inter-group gate G1 located between them. Instead, as shown by the arrows AR41 to AR45, the current path is changed from the main path La to the bridge path Lca, the bypass path Lb, and the , B Ridge Path Lce On the other hand, in the string ST1 excluding the module battery 4(k) to which the two failed cells 5 (5x(1), 5x(2)) belong, the main path La is maintained as the current path, as shown by arrows AR46 and AR47, for example, in the same way as when there is no failure in the cells 5.

[0088] Next, in the string ST2, in order to bypass another cell group 10 belonging to the same storage vessel 11 from the state shown in FIG. 4, the bypass control unit 31b controls the bridge gate 11 provided on the bridge path Lca to G2ais switched from the OFF state to the ON state, while the bridge gate G2b provided on the bridge path Lcb is switched from the ON state to the OFF state.

[0089] At the very least, if these switches are performed, the ON / OFF state of the gate switch in the modular battery 4(k+1) of string ST2 will be the same as the ON / OFF state of the gate switch in the modular battery 4(k) of string ST1 to which the failed cell 5 belongs. Therefore, if only the above-mentioned switches are performed, both of the cell groups 10 included in the storage container 11 that constitutes the modular battery 4(k+1) are bypassed in the current path of string ST2.

[0090] Unlike the case shown in Fig. 5, there is no need to assume that the second failed cell 5 belongs to the same cell group 10 as the first failed cell 5. This is because, in any of the cell groups 10 included in the storage battery set 2, once a certain cell 5 fails, the cell group 10 is bypassed and no current is passed therethrough, so no further failures can occur.

[0091] [Case (iii): In the string ST to which the first failed cell 5 belongs, a cell 5 belonging to a module battery 4 different from the failed cell 5 fails] In this case, the bypass control unit 31b switches the ON / OFF state of the target gate switch so that the cell group 10 is newly bypassed in each of the module battery 4 including the cell group 10 to which the second failed cell 5 belongs, and in each of the module batteries 4 of the other string ST in which the failed cell 5 is not present. In the string ST in which the failed cell 5 is not present, the newly bypassed cell group 10 and the initially bypassed cell group 10 may be contained in the same storage container 11 to constitute one module battery 4, or may be contained in different storage containers 11 to constitute different module batteries 4. When the bypassed cell group 10 is contained in the same storage container 11, the string ST1 in FIG. 5 of A bypass configuration may be employed as illustrated for both storage vessel 11(k) and storage vessel 11(k+1) of string ST2.

[0092] In case (iii), the maximum electromotive force in each string ST will further decrease by mV0, so that the storage battery set 2 will continue to be used as a battery with a maximum electromotive force of 2(n-1)mV0.

[0093] (When 3 or more batteries fail) Even if more cells 5 fail after the second cell 5 fails, the problem can basically be dealt with by switching the ON / OFF state of the gate switch in the case where one or two cells 5 fail as described above, for the gate switch provided in the storage container 11 that contains the cell group 10 to which the newly failed cell 5 belongs.

[0094] However, as the number of failed cells 5 increases, the overload ratio of the remaining cells 5 increases and approaches the limit of the current that flows. Therefore, the number of failed cells 5 permitted in the storage battery set 2 is determined in advance according to the overload ratio and the limit of the current.

[0095] In addition, each time a failure occurs in a cell 5, when switching the current path, the gate switch to be switched between the ON state and the OFF state is selected so as to minimize the increase in the number of gate switches constituting the current path.

[0096] (Features and advantages of bypass control) As described above, in this embodiment, in each module battery 4 of the two strings ST (ST1, ST2) that make up the storage battery set 2, in addition to the main path La in which the single cells 5 are divided into cell groups 10 and connected in series, a bypass path Lb is provided, and gate switches (inter-group gate G1, bridge gates G2a, G2b, G2c, G2d, G2e, module end gate G3) are provided between the cell groups 10 in the main path La and in the bridge path connecting the main path La and the bypass path Lb.

[0097] When there is no failure in any of the single cells 5, current is passed through each string ST using only the main path La. On the other hand, when a single cell 5 in any of the strings ST fails, the ON / OFF state of the gate switch is appropriately switched depending on the location of the failed single cell 5, thereby bypassing the cell group 10 including the failed single cell 5 via the bypass path Lb, and a similar bypass is also performed in the string ST that does not have a failed single cell 5, thereby making the electromotive forces in the two strings ST equal.

[0098] As a result, in the storage battery set 2, even if a configuration is adopted in which the number of series connections of the single cells 5 in each string ST is large while the number of parallel connections of the strings ST is small, the impact of a failure of a single cell 5 on the overall output of the storage battery set 2 is suitably reduced.

[0099] In particular, when the number m of the cells 5 constituting one cell group 10 is kept relatively small while the value n, which is the number of module batteries 4, is increased, the maximum electromotive force is sufficiently secured while the increase in the overload ratio is suppressed.

[0100] More specifically, it is preferable that m is less than 10 (e.g., 8) and n is about several tens (e.g., 35). However, it should be noted that, when the value of n is constant, the smaller the value of m, the greater the number of gate switches required.

[0101] Assuming that a model case is one in which m = 8, n = 35, and the electromotive force V0 of the single cell 5 is 2 V, the total number of single cells in the storage battery set 2 in this model case is 1120, and the maximum electromotive force when no single cell 5 fails is 1120 V. On the other hand, when four single cells 5 fail, the number of unused cells in the storage battery set 2 will be only 64, and the overload ratio will be 2 × 35 / (2 × 35-4) = 1.061.

[0102] Assuming a module battery consisting of 1152 cells connected in parallel to 12 strings, each of which has 96 cells connected in series, as an example of a conventional module battery without a bypass path, the maximum electromotive force of such a module battery is only 96 x 2 = 192 V, despite the large number of cells. Even if only one cell belonging to each of the two strings fails, the overload ratio will be 12 / 10 = 1.09, which exceeds the overload ratio in the model case described above.

[0103] This indicates that by adopting the configuration of the module battery according to the present embodiment, it is possible to realize a module battery with excellent redundancy against failures while reducing the number of unit cells compared to conventional methods.

[0104] Furthermore, in this embodiment, three types of gate switches, an inter-group gate G1, a bridge gate G2, and a module end gate G3, are provided in each string ST constituting the storage battery set 2. When there is no failure in the unit cells 5, only the inter-group gate G1 and the module end gate G3 are in the ON state in each housing container 11, and the bypass control unit 31b switches the ON / OFF state of each gate switch depending on the occurrence of a failure in the unit cells 5 thereafter.

[0105] If the only purpose is to bypass a cell group 10 including a failed battery 5, it is sufficient to provide bridge gates G2a, G2b, G2c, and G2d provided on four bridge paths Lca, Lcb, Lcc, and Lcd connecting the main path La and the bypass path Lb on the upstream and downstream sides of each cell group 10. That is, the inter-group gate G1, the module end gate G3, and the bridge path Lce and the terminal bridge gate G2e provided thereon, or further, the bypass path Lb except for between the bridge gates G2a and G2b and between the bridge gates G2c and G2d, can be omitted.

[0106] Nevertheless, the reason why they are provided in the storage battery set 2 according to the present embodiment is to suppress as much as possible the increase in resistance loss that occurs when the number of gate switches constituting the current path increases by one due to the bypass, as described above. The more gate switches included in the current path, the greater the voltage drop caused by this in the string ST.

[0107] For example, if the above elements that can be omitted are actually omitted, each time a new cell group 10 that needs to be bypassed occurs in a string ST, the number of gate switches through which the bypass must be performed increases by two.

[0108] In contrast, in a configuration in which gate switches are arranged as in this embodiment, when one of the two cell groups 10 contained in the container 11 is bypassed for the first time, the number of gate switches that form the current path increases by one only in the case where the upstream cell group 10 is bypassed, as described above. As shown in Fig. 4, in the case where the downstream cell group 10 is bypassed, the number of gate switches used remains two, unchanged from before the bypass was performed.

[0109] In addition, when another cell group 10, which is contained in the same storage container 11 as the previously bypassed cell group 10 and therefore constitutes a single module battery 4 together, is further bypassed, only two gate switches, the bridge gate G2a and the terminal bridge gate G2e, are turned ON, so the number of gate switches that form the current path is the same as when there is no failure in the single battery 5.

[0110] Therefore, in the storage battery set 2 of this embodiment, the number of gate switches that become current paths during bypass is minimized, and the effect of voltage drop associated with an increase in the number of gate switches that become current paths due to a failure of a single battery 5 is suitably suppressed.

[0111] Furthermore, in the storage battery system 1 of this embodiment, a storage battery set 2 is formed by connecting two identically configured strings ST (ST1, ST2) in parallel, and if a failure occurs in a single cell 5 in one of the strings ST and one or more cell groups 10 including that single cell 5 needs to be bypassed, the same number of cell groups 10 are also bypassed in the other string ST.

[0112] As a result, the maximum electromotive force in each string ST decreases by the same value (specifically, the electromotive force V0 of the cell × the number m of the cells 5 belonging to one cell group 10 × the number of cell groups 10 to which the failed cell 5 belongs). Therefore, even if a cell 5 in one of the strings ST fails, the electromotive forces in the two strings ST remain the same. This also contributes to ensuring redundancy against cell failure.

[0113] <Specific configuration example of storage battery set> A specific configuration example of the storage battery set 2 having the above-mentioned characteristics will be described below. Note that in the following, an example is taken of a cell group 10 being composed of eight cells 5 (when m=8).

[0114] Fig. 6 is a top view illustrating a state in which the single cell 5 is housed in the container 11, and Figs. 7 and 8 are side views of the container 11 in different orientations in this housed state. In other words, Figs. 6 to 8 also show configuration examples of one module battery 4. Note that in Fig. 6 and subsequent figures, right-handed xyz coordinates are used, with the longitudinal direction of the container 11 in plan view (the left-right direction in Fig. 6) being the x-axis direction, the lateral direction in plan view (the up-down direction in Fig. 6) being the y-axis direction, and the vertical direction being the z-direction.

[0115] The container 11 shown in FIG. 6 has an outer surface and an inner surface made of metal plates, and a heat insulating material 11 is provided between the metal plates on the side and the bottom. A is It is a filled rectangular container.

[0116] The bottom and sides of the storage container 11 are supported by a support frame 11b, and the upper ends of the four corners of the support frame 11b are provided with mounting portions 11b1 on which other storage containers 11 can be stacked. AccumulatedThe container 11 has a mounting portion 11c on which layers can be placed. That is, the container 11 has a structure that can be stacked in the vertical direction. In the following description, the side surfaces of the container 11 along the longitudinal direction in plan view are referred to as a pair of main side surfaces 11s1, and the side surfaces along the lateral direction in plan view are referred to as a pair of sub-side surfaces 11s2.

[0117] 6 and 7 show two cell groups 10, each consisting of eight cylindrical cells 5(1)-5(8), arranged in two rows along the x-axis direction and housed in the housing container 11. Although not shown in Figs. 6 to 8, the housing container 11 also includes the above-mentioned heater 11h, fan 11f, and temperature sensor 11t at appropriate locations.

[0118] More specifically, a lid (not shown) is placed on top of the storage container 11 in order to ensure insulation within the storage container 11. The lid, like the storage container 11, has an outer and inner surface made of metal plates and is filled with a heat insulating material inside. In addition, any gaps other than those between the objects placed inside the storage container 11 are filled with sand. The sand is filled in order to reduce the impact on the surroundings in the event of a malfunction such as breakage, abnormal heating, or leakage of active material in the unit cells 5. Examples of sand include expanded vermiculite and silica sand.

[0119] A negative electrode terminal 5n protrudes from the center of one end of the cell 5 (the upper end when housed in the container 11), and a positive electrode terminal 5p protrudes from the periphery. In each cell group 10, the positive electrode terminal 5p of one cell and the negative electrode terminal 5n of the other cell 5 arranged adjacent to each other along the longitudinal direction of the container 11 in a plan view are electrically connected by a connection terminal C1. However, only some of the connection terminals C1 are shown in FIG. 6.

[0120] In addition, the unit cell 5(1) arranged at one end of each cell group 10 Negative terminal 5n and a single cell 5 (8) disposed at the other end. Positive terminal 5pAn external connection terminal C2 protruding from the main side surface 11s1 to the outside of the container 11 is connected to the main side surface 11s1. connection Terminals C2 and the metal plate constituting the container 11 are insulated from each other by a predetermined insulating material.

[0121] 7 and 8, one of the sub-side surfaces 11s2 of the storage container 11 is provided with a connection portion 20 (not shown in FIG. 6).

[0122] The connection part 20 includes a first connection copper plate 21, a second connection copper plate 22, a third connection copper plate 23, a fourth connection copper plate 24, a fifth connection copper plate 25, and a sixth connection copper plate 26. The first to sixth connection copper plates 21 to 26 are made of copper plates having a thickness of about 0.3 mm to 3.0 mm. Alternatively, a plate-shaped base material having a similar thickness with copper foil attached thereto may be used. As described later, the first to sixth connection copper plates 21 to 26 are provided as a current path during operation of the storage battery set 2. The first to fourth connection copper plates 21 to 24 are provided by bending from the secondary side surface 11s2 of the storage container 11 toward either of the pair of primary side surfaces 11s1.

[0123] 7 shows how the cell group 10 located on the front side as viewed in the drawing is electrically connected to the connection portion 20 on one of the pair of main side surfaces 11s1. Specifically, the cable C4 connects the external connection terminal C2 connected to the unit cell 5(1) to one end of the first connection copper plate 21, and the cable C3 connects the external connection terminal C2 connected to the unit cell 5(8) to one end of the second connection copper plate 22.

[0124] Although not shown, the other cell group 10 and the connection portion 20 are also electrically connected by a cable (not shown) on the other of the pair of main side surfaces 11s1. That is, the external connection terminal C2 connected to the unit cell 5(1) is connected to one end of the third connection copper plate 23, and the external connection terminal C2 connected to the unit cell 5(8) is connected to one end of the fourth connection copper plate 24.

[0125] 8, a gate switch G is provided between each of the first connection copper plate 21 to the fourth connection copper plate 24 and the fifth connection copper plate 25. Further, gate switches G are provided between the second connection copper plate 22 and the third connection copper plate 23, between the fourth connection copper plate 24 and the sixth connection copper plate 26, and between the fifth connection copper plate 25 and the sixth connection copper plate 26.

[0126] The electrical connections in the container 11 by the connection terminal C1, the external connection terminal C2, the cables C3 and C4, etc., correspond to the circuit configuration shown in FIG.

[0127] That is, the bridge paths Lca to Lcd are provided between the first connection copper plate 21 to the fourth connection copper plate 24 and the fifth connection copper plate 25, and the gate switches G provided therein are bridge gates G2a, G2b, G2c, and G2d, respectively. Furthermore, the gate switch G between the second connection copper plate 22 and the third connection copper plate 23 corresponds to an inter-group gate G1. Moreover, the gate switch G between the fourth connection copper plate 24 and the sixth connection copper plate 26 corresponds to a module end gate G3. And the gate switch G between the fifth connection copper plate 25 and the sixth connection copper plate 26 corresponds to a terminal gate G4. bridge This corresponds to gate G2e.

[0128] The main path La corresponds to the path from the first connection copper plate 21 → (cable C4, external connection terminal C2) → cell group 10 (series of battery cell 5(1) to battery cell 5(8)) → (external connection terminal C2, cable C3) → second connection copper plate 22 → gate switch G (G1) → third connection copper plate 23 → (cable, external connection terminal C2) → cell group 10 (series of battery cell 5(1) to battery cell 5(8)) → (external connection terminal, cable C4) → fourth connection copper plate 24 → gate switch G (G3) → sixth connection copper plate 26.

[0129] The fifth connection copper plate 25 corresponds to the bypass path Lb in the container 11 .

[0130] In addition, the other end 21a of the first connection copper plate 21 and the other end 26a of the sixth connection copper plate 26 each serve as a terminal portion for electrical connection with another storage container 11.

[0131] For example, when the container 11 shown in FIG. 6 to FIG. 8 is a container for storing the battery module 4(k) of the failed string ST1 of the battery cell 5x(1) shown in FIG. 4, the current path during bypass is the first connection copper plate 21 → (cable C4, external connection terminal C2) → cell group 10 (series of the battery cell 5(1) to the battery cell 5(8)) → (external connection terminal C2, cable C3) → second connection copper plate 22 → gate switch G (G2b) → fifth connection copper plate 25 → gate switch G (G2 e ) →6th connecting copper plate 26.

[0132] From the above, FIGS. 6 to 8 show that a module battery 4 having the circuit configuration illustrated in FIG. 2 can actually be realized.

[0133] Fig. 9 is a diagram showing a schematic configuration of a module battery housing body 100 in which a plurality of housing containers 11 each having the configuration shown in Fig. 6 to Fig. 8 are housed in one container 100c. In Fig. 9, the same xyz coordinates as Fig. 6 to Fig. 8 are used in relation to the housing containers 11. Hereinafter, it is assumed that each string ST of the storage battery set 2 is made up of 35 housing containers 11 (n=35).

[0134] 9, 12 locations×3 rows=36 storage container locations are prepared in two rows for each string ST (ST1, ST2) on the container 100c, and 35 storage containers 11 for each string ST are arranged in 35 locations in each row excluding one end side of the lowest row. Note that one location on one end side of the lowest row, the bottom of which is shown with hatching, is used as an arrangement location for the terminal unit 12 for both rows.

[0135] More specifically, in each string ST, the housing container 11 has the connection portions 20 each connected to the side surface ( yz That is, in each of the containers 11, the connection portion 20 is disposed so as to be exposed to the oblique line portion.

[0136] As described above, each storage container 11 has the placement portion 11b1 and the placement portion 11c, so that stacking as shown in FIG. 9 can be suitably performed.

[0137] With the storage containers 11 stacked in this manner, the other end 21a of the first connecting copper plate 21 and the other end 26a of the sixth connecting copper plate 26 of different storage containers 11 can be connected to actually construct a storage battery set 2 having the circuit configuration shown in Figures 1 and 2.

[0138] As described above, according to this embodiment, in a storage battery system having a string formed by connecting in series a large number of single cells, each of which is a high-temperature operating secondary battery, the single cells constituting the string are divided into a plurality of cell groups, and bypass paths are provided that allow each cell group to be individually bypassed within the string. Thus, even if a single cell fails, it is possible to continue supplying electricity to the string including the single cell by bypassing at least one cell group including the cell group to which the single cell belongs.

[0139] As a result, according to this embodiment, a module battery with excellent redundancy against failure of a single cell and a rechargeable battery system including the same can be realized.

[0140] In addition, in the battery storage system according to the present embodiment, gate switches are provided between the cell groups connected in series with each other and in the bridge paths connecting the upstream and downstream sides of each cell group with the bypass path, and when bypassing the current path, the number of gate switches located in the current path is minimized by appropriately combining the ON / OFF states of the gate switches. This makes it possible to suitably reduce the effect of voltage drops that accompany switching of the gate switches due to failure of a single cell.

[0141] Furthermore, in the battery system according to the present embodiment, two strings having the same configuration are connected in parallel, and when a cell group including a cell in one string is bypassed due to a failure of the cell in the one string, a cell group in the other string is also bypassed. This reduces the maximum electromotive force in each string by the same value. Therefore, even if a cell in one string fails, the electromotive forces in the two strings remain the same. This also contributes to ensuring redundancy against failure of a cell.

[0142] Furthermore, in the storage battery system according to the present embodiment, when a cell fails, the ON / OFF state of each gate switch is switched for the module battery including that cell, and does not affect other module batteries belonging to the same string. In other words, the ON / OFF state switching control is completed within each module battery. Furthermore, as long as the increase in the number of gate switches used is suppressed only in the module battery that is the target of the ON / OFF state switching control, the number of gate switches used in the entire string does not increase.

[0143] In particular, when the number of cells constituting one cell group is kept relatively small while the number of storage containers is increased, the maximum electromotive force is sufficiently secured while the increase in the overload ratio of the cells is suppressed.

[0144] <Modification> In the above-described embodiment, an example is shown in which one storage battery set 2 is composed of two strings ST connected in parallel to each other, but this is not a required aspect, and more strings ST may be connected in parallel.

[0145] However, the configuration in which one storage battery set 2 is composed of two strings ST is preferable in that it is easy to arrange all of the storage containers 11 constituting the module batteries 4 each belonging to each string ST without any gaps and so as to form the outer surface of the module battery housing 100, as in the module battery housing 100 shown in Figure 9.

[0146] In the above embodiment, the switching of the current path between the main path La and the bypass path Lb is performed using a gate switch made of a semiconductor element SD, but instead of this, such switching may be performed using a mechanical switch. In that case, the way in which each cell group is connected to the switch may be different from that of the above embodiment, as long as the same bypass as that of the above embodiment is realized.

Claims

1. A storage battery set comprising at least one string of a number of single cells, each of which is a high-temperature operating secondary battery, connected in series, The large number of single cells constituting the at least one string are divided into a plurality of cell groups, a main path in which the plurality of cell groups are connected in series; a bypass path capable of individually bypassing each of the plurality of cell groups within the at least one string; Equipped with Gate switches made of semiconductor elements capable of switching a conducting state between ON / OFF are provided between cell groups among the plurality of cell groups that are connected in series to each other in the main path and in a bridge path that connects the upstream and downstream sides of each cell group to the bypass path, Among the plurality of cell groups, one module battery is configured for each two cell groups connected in series to each other, the bypass path is provided for each of the battery modules, The module battery serves as the gate switch, an inter-group gate provided between the two cell groups in the main path; a module end gate provided in the main path between the downstream side of the two cell groups and another module battery connected to the module battery; four bridge gates connecting the upstream and downstream sides of the two cell groups in the main path to the bypass path provided in the module battery; a terminal bridge gate that connects the most downstream side of the main path and the bypass path provided in the module battery; Equipped with When at least one of the large number of single cells fails, the gate switch corresponding to the cell group to which the failed single cell belongs is switched between ON / OFF, so that the current path is bypassed from the main path to the bypass path at the cell group to which the failed single cell belongs. A storage battery set characterized by:

2. 2. The battery set according to claim 1, Each of the module batteries is housed in a housing, The container is equipped with a heater and a cooling fan, In the storage container, the unit cells belonging to the two cell groups are arranged for each cell group and stored in two rows, a connection portion including the inter-group gate, the module end gate, the four bridge gates, and the terminal bridge gate is provided on one side of the container perpendicular to the arrangement direction of the unit cells. A storage battery set characterized by:

3. The storage battery set according to claim 1 or 2, The plurality of cell groups are composed of eight single cells. A storage battery set characterized by:

4. The storage battery set according to claim 1 or 2, the at least one string is a first string and a second string; When the current path is bypassed in the first string, current paths of cell groups in the second string are bypassed in the same number as the number of cell groups bypassed in the first string. A storage battery set characterized by:

5. The battery set of claim 1 or claim 2, further comprising an AC-DC converter connected to the at least one string; A controller for controlling the storage battery set; Equipped with The battery set is connected to a transformer. A battery storage system characterized by:

6. The battery system according to claim 5, A plurality of the battery sets; A plurality of the controllers for controlling the respective storage battery sets; Equipped with the plurality of battery sets are connected in parallel to the transformer; A battery storage system characterized by:

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