Battery system

Abstract

The battery system (1) comprises a plurality of battery modules (10) connected to a load (100) and a control device (60). The battery module (10) comprises a precharge unit (40) having a pre-resistance (41). The control device (60) comprises a precharge processing execution unit (67) that executes precharge processing on one battery module (10) among the plurality of battery modules (10). The control device (60) further comprises a time acquisition unit (64) that acquires a cooling time TC, which is the elapsed time from the previous precharge processing of the battery module ranked first in the previous sequence, which was the first to execute precharge processing when connected to the previous load (100), and a sequence determination unit (65) that determines the sequence so that precharge processing is not executed first for the battery module ranked first in the previous sequence when the cooling time TC is less than or equal to a predetermined reference time TD. By doing so, the uneven degradation of the pre-resistance can be suppressed.

Description

Technology Field

[0001] The present invention relates to a battery system. Background Technology

[0002] For example, Patent Document 1 discloses a battery system for supplying power to an external load. This battery system comprises a plurality of battery modules. Each battery module comprises a precharge unit having a free resistor. Furthermore, this battery system is configured to perform a precharge process that allows current to flow from the battery module to the load through the free resistor when each battery module is connected to the load. By doing so, it is possible to suppress inrush currents exceeding the rated current from flowing to the load. Prior art literature

[0003] Japanese Application Publication No. 2024-170768 The problem to be solved

[0004] However, in the battery system described in Patent Document 1, there were cases where the free resistance of only a specific battery module among a plurality of battery modules deteriorated. The technology disclosed herein aims to suppress such uneven deterioration of free resistance. means of solving the problem

[0005] The battery system disclosed herein comprises a pair of output terminals connected to a load, a plurality of battery modules connected to the pair of output terminals and arranged in parallel, and a control device. Each of the plurality of battery modules comprises a battery unit having a plurality of single cells connected in series, a main relay provided at the end of the first side of the battery unit, a unit relay provided at the end of the second side of the battery unit, and a precharge unit provided in parallel with the main relay. The precharge unit comprises a pre-resistor and a precharge relay connected in series with the pre-resistor. The control device comprises a precharge processing execution unit that controls the connection of the plurality of battery modules to the pair of output terminals after performing precharge processing on one of the plurality of battery modules at a time when the plurality of battery modules are connected to the load through the pair of output terminals. The above precharge processing is a process in which, for the one battery module of the target, the main relay is turned OFF and the unit relay and the precharge relay are turned ON, and then, when the difference between the main voltage applied between the pair of output terminals and the unit voltage of the battery unit in the one battery module is less than or equal to a predetermined threshold, the main relay of the one battery module is turned ON and the precharge relay is turned OFF. Furthermore, the control device of the battery system disclosed herein has a cooling time T, which is the elapsed time from the previous precharge processing of the battery module ranked first in the previous sequence, where the precharge processing was first executed during the previous connection to the load. C A time acquisition unit for acquiring , and the cooling time T C a predetermined standard time T DIn the case below, a sequence determining unit is further provided to determine the sequence of the precharge processing so that the precharge processing is not executed first for the battery module of the previous sequence 1 when connecting to the above load in the next session.

[0006] In conventional battery systems, pre-charge processing is performed sequentially on multiple battery modules. At this time, a very large current flows through the free resistor of the battery module that is pre-charged first (hereinafter also referred to as the "first-ranked battery module"). Consequently, the free resistor of the first-ranked battery module is prone to heating during pre-charge processing. Furthermore, if pre-charge processing is performed again on the previous first-ranked battery module without allowing sufficient cooling time, the free resistor becomes very hot. If pre-charge processing is repeated without providing sufficient cooling time in this manner, only the free resistor of the first-ranked battery module deteriorates preferentially. In contrast, the battery system disclosed herein [describes] a cooling time T, which is the elapsed time since the previous pre-charge processing of the previous first-ranked battery module. C Acquires. And, this cooling time T C a reference time T D In the case below, it is determined that the pre-resistance of the battery module ranked first in the previous sequence has not been sufficiently cooled, and the order of pre-charge treatment is determined so that another battery module becomes the first in the next sequence. By doing so, since the pre-charge treatment for high-temperature pre-resistance can be prevented, the uneven degradation of pre-resistance among multiple battery modules can be suppressed. Brief explanation of the drawing

[0007] FIG. 1 is a schematic diagram illustrating a battery system according to an embodiment. FIG. 2 is a diagram illustrating the elapsed time and cooling time in the technology disclosed herein. FIG. 3 is a flowchart showing the procedure for performing precharge processing on the first to third battery modules. Figure 4 is a flowchart showing the detailed procedure of step S103 in Figure 3. FIG. 5 is a timing chart showing the sequence of performing precharge processing on the first to third battery modules. Specific details for implementing the invention

[0008] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. Furthermore, the embodiment described herein is, of course, not intended to particularly limit the present invention. Each drawing is a schematic diagram and does not necessarily faithfully reflect an actual embodiment. Additionally, members and parts exhibiting the same function are appropriately given the same reference numerals, and redundant descriptions are appropriately omitted.

[0009] FIG. 1 is a schematic diagram illustrating a battery system (1) according to the present embodiment. As shown in FIG. 1, the battery system (1) is connected to a load (100). The load (100) is not particularly limited, but is, for example, a driving device such as an electric motor of a vehicle, or an inverter. A smoothing capacitor for reducing sudden changes in current may be connected to the load (100). Here, the battery system (1) is installed in a vehicle such as a hybrid vehicle or an electric vehicle, for example, and is used as a power source to supply power to an electric motor that drives the vehicle. However, the battery system (1) is not limited to use in vehicles.

[0010] The battery system (1) is equipped with a pair of output terminals (5), a plurality of battery modules (10), and a control device (60). The pair of output terminals (5) is connected to a load (100). Here, one of the pair of output terminals (5) is a positive terminal, and the other output terminal (5) is a negative terminal.

[0011] A plurality of battery modules (10) are connected to a pair of output terminals (5). In this embodiment, a plurality of battery modules (10) are connected to a main bus (8), and a pair of output terminals (5) are connected to the main bus (8). Therefore, a plurality of battery modules (10) are connected to a pair of output terminals (5) through the main bus (8). Additionally, a plurality of battery modules (10) are indirectly connected to a load (100) through a pair of output terminals (5). The load (100) can convert the power of the battery modules (10) into power or supply regenerative power to the battery modules (10). A plurality of battery modules (10) are arranged (in other words, connected) in parallel. Also, the number of battery modules (10) is not particularly limited, but in this embodiment, there are three. Here, the three battery modules (10) are appropriately referred to as the first battery module (10A), the second battery module (10B), and the third battery module (10C). The battery module (10) has the first battery module (10A), the second battery module (10B), and the third battery module (10C). In the following description, the term "battery module (10)" is used for common descriptions of the first battery module (10A) to the third battery module (10C).

[0012] In this embodiment, the configuration of the first battery module (10A) to the third battery module (10C) is identical. One battery module (10) is equipped with a plurality of single cells (11), a main relay (20), a unit relay (30), a precharge unit (40), and a battery control device (50). The single cells (11) are capable of charging and discharging. As the single cells (11), for example, a secondary battery capable of repeated charging and discharging by moving a charge carrier between a pair of electrodes (e.g., a positive electrode and a negative electrode) through an electrolyte may be used. For example, a lithium-ion secondary battery or a nickel-hydrogen battery may be used as the single cells (11). A plurality of single cells (11) are connected in series. Here, a plurality of single cells (11) are connected in series through a bus bar not shown. The number of single cells (11) in one battery module (10) is not particularly limited and is a predetermined number. In this embodiment, the number of single cells (11) in one battery module (10) is 5. The number of single cells (11) in the first battery module (10A) to the third battery module (10C) is the same, but may be different. Here, a plurality of single cells (11) connected in series is referred to as a battery unit (12). A battery unit (12) has a plurality of single cells (11) connected in series.

[0013] The main relay (20) is connected in series with a plurality of single cells (11) (in other words, the battery unit (12)). Here, the main relay (20) is provided at the first end of the battery unit (12). Here, the "first end" refers to the positive end of the battery unit (12) (in other words, the plurality of single cells (11)). However, the first end may also be the negative end of the battery unit (12). That is, the main relay (20) may be provided at the negative end of the battery unit (12). The main relay (20) is a relay that switches the ON and OFF of the connection between the first end of the battery unit (12) and the load (100).

[0014] In addition, in this embodiment, turning the relay ON means a connected state (e.g., a closed state). Turning the relay OFF means a disconnected state (e.g., an open state).

[0015] A unit relay (30) is connected in series with a plurality of single cells (11) (in other words, a battery unit (12)). Here, the unit relay (30) is provided at the second end of the battery unit (12). The "second end" is the end opposite to the first end of the battery unit (12) (in other words, a plurality of single cells (11)). Here, the "second end" is the end on the negative side of the battery unit (12). However, the second end may also be the end on the positive side of the battery unit (12). That is, the unit relay (30) may be provided at the end on the positive side of the battery unit (12). The unit relay (30) is a relay that switches the ON and OFF of the connection between the second end of the battery unit (12) and the load (100).

[0016] The precharge unit (40) is provided in parallel with respect to the main relay (20). In other words, the precharge unit (40) is connected in parallel with the main relay (20). Here, the precharge unit (40) is provided at the end of the first side (here, the end of the positive side) of the battery unit (12) (e.g., a plurality of single cells (11) connected in series). The precharge unit (40) is a circuit that suppresses the flow of inrush current to the load (100) when power is supplied from the battery system (1) to the load (100). The configuration of the precharge unit (40) is not particularly limited. Here, the precharge unit (40) is equipped with a pre-resistor (41) and a precharge relay (42) connected in series with the pre-resistor (41). The precharge relay (42) is capable of switching the connection ON and OFF.

[0017] The battery control device (50) is connected to a plurality of single cells (11). The battery control device (50) is constructed by a substrate and provides so-called registers. The battery control device (50) may be constructed by, for example, a microcontroller. The battery control device (50) has a single cell voltage detector (51), an equalizer (52), and a battery unit voltage detector (53).

[0018] The single cell voltage detector (51) detects the single cell voltage of each of the plurality of single cells (11) constituting the battery unit (12). The single cell voltage detector (51) is realized, for example, by a circuit capable of detecting the voltage of each of the plurality of single cells (11). The single cell voltage detector (51) may have a plurality of connection terminals connected to the positive and negative electrodes of each single cell (11) constituting the battery unit (12), for example.

[0019] The equalizer (52) equalizes the residual capacity of a plurality of single cells (11) constituting a battery unit (12) based on the single cell voltage of the single cell (11) detected by the single cell voltage detector (51). As long as the equalizer (52) can equalize the residual capacity of a plurality of single cells (11), its specific configuration is not particularly limited. The equalizer (52) is realized by a so-called equalization circuit. Although not illustrated, the equalizer (52) may be realized by a plurality of discharge circuits and a control circuit connected between a plurality of connection terminals connected to the positive and negative electrodes of the single cell (11), for example. Each of the plurality of discharge circuits is equipped with a discharge resistor and a switching element. The control circuit is configured to obtain the single cell voltage of each of the plurality of single cells (11) from the single cell voltage detector (51). The control circuit obtains the single cell voltage of each of the plurality of single cells (11) from the single cell voltage detector (51) through, for example, a multiplexer not shown. Then, the control circuit is configured to enable the switching of the switching element ON and OFF based on the obtained single cell voltage, and to appropriately discharge the single cell voltage of the single cell (11) with a high voltage to match the single cell (11) with a low voltage.

[0020] The battery unit voltage detector (53) detects the unit voltage of a plurality of single cells (11) (in other words, the battery unit (12)) connected in series. The battery unit voltage detector (53) is realized, for example, by a circuit capable of detecting the unit voltage of the battery unit (12). The battery unit voltage detector (53) has a plurality of connection terminals connected to the positive and negative electrodes of the plurality of single cells (11) constituting the battery unit (12). The battery unit voltage detector (53) may detect the unit voltage of the battery unit (12) by, for example, summing the single cell voltages of each single cell (11) detected by the single cell voltage detector (51).

[0021] The control device (60) is configured, for example, by a microcontroller. The control device (60) is equipped with a communication interface, a central processing unit (CPU) that executes commands of a control program, a read-only memory (ROM) that stores a program executed by the CPU, a random access memory (RAM) used as a working area for executing the program, and a memory that stores the program and various data. The control device (60) is electrically connected to the main relay (20), unit relay (30), precharge relay (42) of a precharge unit (40), and the battery control device (50) of a plurality of battery modules (10) (here, the first battery module (10A) to the third battery module (10C)). The control device (60) controls the switching of the main relay (20), unit relay (30), and precharge relay (42) to ON and OFF for each battery module (10). In this embodiment, as shown in FIG. 1, a power source (70) is connected to the control device (60). Power is supplied to the control device (60) from the power source (70).

[0022] In this embodiment, as illustrated in FIG. 1, the control device (60) is equipped with a main voltage acquisition unit (61), a unit voltage acquisition unit (63), a time acquisition unit (64), a sequence number determination unit (65), a precharge processing execution unit (67), and a memory unit (69). The main voltage acquisition unit (61), the unit voltage acquisition unit (63), the sequence number determination unit (65), the precharge processing execution unit (67), and the memory unit (69) may be implemented by one or more processors or by circuits.

[0023] The main voltage acquisition unit (61) acquires the total main voltage of a plurality of battery modules (10) connected in parallel. In other words, the main voltage acquisition unit (61) acquires the main voltage applied between a pair of output terminals (5). In other words, the main voltage acquisition unit (61) acquires the main voltage between the main buses (8). Furthermore, as long as the main voltage can be acquired, the configuration of the main voltage acquisition unit (61) is not particularly limited. For example, the main voltage acquisition unit (61) may be realized by a circuit capable of detecting the main voltage between a pair of output terminals (5). The main voltage acquisition unit (61) may be provided with a connection terminal connected to, for example, the main bus (8) on the positive side and the main bus (8) on the negative side (or a pair of output terminals (5)).

[0024] The unit voltage acquisition unit (63) acquires a unit voltage, which is the voltage of the battery unit (12), for each of the plurality of battery modules (10). Here, the unit voltage acquisition unit (63) acquires the unit voltage of the first battery module (10A) to the third battery module (10C). In this embodiment, the unit voltage acquisition unit (63) acquires the unit voltage from the battery unit voltage detector (53) of the battery control device (50) of each battery module (10). Here, the battery unit voltage detector (53) detects the unit voltage of the battery unit (12) and transmits the detected unit voltage to the control device (60). The unit voltage acquisition unit (63) acquires the unit voltage by receiving the unit voltage transmitted from the battery unit voltage detector (53).

[0025] The precharge processing execution unit (67) performs precharge processing for each of the multiple battery modules (10) when the multiple battery modules (10) are connected to the load (100) through a pair of output terminals (5). The precharge processing execution unit (67) performs precharge processing for one battery module (10) among the multiple battery modules (10). In this embodiment, the precharge processing execution unit (67) performs precharge processing independently for the first battery module (10A), the second battery module (10B), and the third battery module (10C). For example, the precharge processing execution unit (67) performs precharge processing for the first battery module (10A), and after the precharge processing for the first battery module (10A) is completed, the precharge processing execution unit (67) performs precharge processing for the second battery module (10B). Then, after the precharge processing for the second battery module (10B) is finished, the precharge processing execution unit (67) performs precharge processing for the third battery module (10C).

[0026] Here, pre-charge processing is a process for suppressing inrush current flowing to the load (100) by controlling the flow of current to the pre-charge unit (40) when the battery unit (12) of the battery module (10) is connected to the load (100) through a pair of output terminals (5). In pre-charge processing, current is not flowed to the main relay (20), but current is actively flowed to the pre-charge unit (40), thereby suppressing inrush current flowing to the load (100). In this embodiment, for the target battery module (10), the main relay (20) is turned OFF and the unit relay (30) and pre-charge relay (42) are turned ON, and then the difference between the main voltage applied between the pair of output terminals (5) and the unit voltage of the battery unit (12) in one battery module (10) is a predetermined threshold V thIn the case below (see FIG. 2), the main relay (20) of one battery module (10) is turned ON, and the precharge relay (42) is turned OFF. Here, the precharge process is performed by turning the unit relay (30) ON after the main relay (20), unit relay (30), and precharge relay (42) are in a state where they are OFF, and then turning the precharge relay (42) ON, and the difference between the main voltage and the unit voltage is a threshold V th After the above, the main relay (20) is turned ON and the precharge relay (42) is turned OFF.

[0027] The time acquisition unit (64) is a cooling time T which is the elapsed time ΔT from the previous precharge processing of the battery module (10) of the previous sequence 1, where the precharge processing was first executed when connected to the previous load. C ...is obtained. Hereinafter, the elapsed time ΔT and cooling time T in this specification C This is explained. FIG. 2 is a diagram illustrating the elapsed time and cooling time in the technology disclosed herein. First, "elapsed time ΔT" in this specification refers to the time from when the most recent precharge process was first executed. Specifically, in the example shown in FIG. 2, the first battery module (10A) is in the first position during the n-1st precharge process. In this case, the elapsed time ΔT of the first battery module (10A) u1 ...is the time from the start of the (n-1)th precharge process to the start of the nth precharge process. Additionally, the second battery module (10B) is in the first position during the (n-3)th precharge process. In this case, the elapsed time ΔT of the second battery module (10B) u2...is the time from the start of the (n-3)th precharge process to the start of the nth precharge process. Also, the third battery module (10C) is in the 1st position during the (n-2)th precharge process. In this case, the elapsed time ΔT of the third battery module (10C) u3 ...is the time from the start of the (n-2)th precharge process to the start of the nth precharge process. And, in the example illustrated in FIG. 2, the first battery module (10A) is the "battery module ranked 1st in the previous sequence" that underwent the previous (n-1)th precharge process. In this case, the time acquisition unit (64) is the elapsed time ΔT of the first battery module (10A). u1 ...cooling time T C ...is considered as 」. And, the time acquisition unit (64) considers the elapsed time ΔT of the first battery module (10A). u1 ...cooling time T C ...is transmitted to the sequence determining unit (65) as 」. Also, in this embodiment, the elapsed time ΔT of another battery module (10) u2 , ΔT u3 It is also transmitted to the sequence number determination unit (65).

[0028] The sequence determining unit (65) determines the sequence for performing precharge processing on a plurality of battery modules (10). Here, in the present embodiment, the sequence determining unit (65) determines the cooling time T C a predetermined standard time T D In the case below, the order of precharge processing is determined so that precharge processing is not performed first on the battery module with the highest sequence number when connecting to the next load (100). By doing so, since precharge processing is prevented from being repeated on a battery module (here, the first battery module (10A)) in which the pre-resistance (41) is not sufficiently cooled, the uneven degradation of the pre-resistance (41) in multiple battery modules (10) can be suppressed.

[0029] Below, detailed control by the sequence determination unit (65) will be described. FIG. 3 is a flowchart showing the procedure for performing precharge processing on the first to third battery modules. FIG. 4 is a flowchart showing the detailed procedure of step S103 in FIG. 3. FIG. 5 is a timing chart showing the procedure for performing precharge processing on the first to third battery modules. Here, before the flowchart of FIG. 3 begins, as at time t0 of FIG. 5, the main relay (20), unit relay (30), and precharge relay (42) in the first battery module (10A) to the third battery module (10C) are in an OFF state.

[0030] First, in step S101 of FIG. 3, the unit voltage acquisition unit (63) of FIG. 1 obtains the unit voltage V of the first battery module (10A). u1 , unit voltage V of the second battery module (10B) u2 , unit voltage V of the third battery module (10C) u3 The unit voltage acquisition unit (63) obtains the unit voltage V from each battery unit voltage detector (53) of the first battery module (10A) to the third battery module (10C). Here, the unit voltage acquisition unit (63) obtains the unit voltage V from each battery unit voltage detector (53) of the first battery module (10A) to the third battery module (10C). u1 , V u2 , V u3 It acquires the unit voltage V acquired by the unit voltage acquisition unit (63). In addition, the unit voltage V acquired by the unit voltage acquisition unit (63) u1 , V u2 , V u3 It is stored in the memory unit (69) (see FIG. 1).

[0031] Next, in step S102, the time acquisition unit (64) has a cooling time T of the battery module ranked 1st in the previous sequence. C The time acquisition unit (64) in this embodiment acquires the elapsed time ΔT from when the most recent precharge processing was first executed for each of the plurality of battery modules (10A to 10C). Specifically, the time acquisition unit (64) in this embodiment acquires the elapsed time ΔT from when the most recent precharge processing was first executed for each of the plurality of battery modules (10A to 10C). u1 to ΔT u3It acquires the elapsed time ΔT. And, the time acquisition unit (64) acquires the elapsed time ΔT u1 to ΔT u3 This shortest battery module (10) is considered as the battery module ranked 1st in the previous sequence, and the elapsed time of the battery module is the cooling time T C It is considered as. This elapsed time ΔT u1 to ΔT u3 and cooling time T C Since the measurement procedure has already been explained, a redundant explanation is omitted. Additionally, the following description will use the case where the first battery module (10A) was the battery module ranked 1st in the previous sequence (see FIG. 2) as an example.

[0032] Next, in step S103 of FIG. 3, the sequence determining unit (65) of FIG. 1 determines the sequence for performing precharge processing for the first battery module (10A) to the third battery module (10C). In the battery system (1) according to the present embodiment, the sequence for performing precharge processing is determined according to the procedure shown in FIG. 4.

[0033] First, as shown in step S10 of FIG. 4, the sequence determining unit (65) obtains the unit voltage V in step S101. u1 , V u2 , V u3 Based on this, a plurality of battery modules (10A to 10C) are arranged in descending order. For example, in this embodiment, the unit voltage V u1 , V u2 , V u3 The values ​​are made to decrease in that order. In this case, the execution order is set as the first battery module (10A), the second battery module (10B), and the third battery module (10C) as candidates for the execution order of the next (n-th) precharge processing.

[0034] Next, in step S20, the sequence determining unit (65) has a cooling time T C (i.e., the elapsed time ΔT of the first battery module (10A)u1 ) is the reference time T D Determines whether it is less than or equal to. Here, cooling time T C a reference time T D In the case where it exceeds ("No" in Step S20), it is understood that the free resistor (41) of the battery module in the previous sequence 1 (the first battery module (10A)) has been sufficiently cooled. For this reason, the sequence determining unit (65) [determines] the unit voltage V u1 , V u2 , V u3 The process proceeds to step S30 without changing the execution order set based on [the method]. Then, in step S30, after determining the execution order of the precharge process, the process proceeds to S105 of FIG. 3.

[0035] Meanwhile, cooling time T C a reference time T D In the case below ("Yes" of Step S20), it is determined that the pre-resistance (41) of the battery module ranked 1st in the previous sequence is still at a high temperature. In this case, the order of the pre-charge processing is changed so that the pre-charge processing is not performed first on the battery module ranked 1st in the previous sequence during the next (nth) pre-charge processing.

[0036] Specifically, the sequence determining unit (65) determines all elapsed times ΔT of a plurality of battery modules (10A to 10C). u1 to ΔT u3 This reference time T D It is determined whether it is less than or equal to (Step S40). Then, the elapsed time ΔT of the plurality of battery modules (10A to 10C) u1 to ΔT u3 Among them, reference time T DIf there is a case where it exceeds ("No" in step S40), it is understood that there is a battery module (10) in which the pre-resistance (41) is sufficiently cooled. In this case, the sequence determining unit (65) proceeds to step S50 in FIG. 4 and, when connecting to the next load (100), changes the order of pre-charge processing for the battery module (first battery module (10A)) that was previously in the first sequence to the second sequence or later. For example, in the example shown in FIG. 2, the sequence determining unit (65) postpones the sequence of the first battery module (10A) in the next (n-th) pre-charge processing to the second sequence. Then, elapsed time ΔT u2 a reference time T D The second battery module (10B) that exceeds the first is moved forward to the first position in the sequence. After this change in order, the sequence determining unit (65) proceeds the processing to step S30 to determine the execution order, and then proceeds the processing to S105 in FIG. 3. By doing so, the first precharge processing, which is prone to heat generation of the pre-resistor (41) due to inrush current, can be prevented for the first battery module (10A) in which the pre-resistor (41) is not sufficiently cooled.

[0037] In addition, in step S40, all elapsed time ΔT of the plurality of battery modules (10A to 10C) u1 to ΔT u3 This reference time T DIn the case below (the "example" of step S40), it is understood that the free resistors (41) of all battery modules (10A to 10C) have not been sufficiently cooled. In this case, the control device (60) performs a predetermined error processing (S60). For example, the battery system (1) according to the present embodiment performs a processing that prohibits turning ON each of the main relay (20), unit relay (30), and precharge relay (42) as an error processing. By doing so, it is possible to prevent the precharge processing from starting while all free resistors (41) are in a high-temperature state, thereby allowing for more suitable suppression of thermal degradation of the free resistors (41).

[0038] As described above, after determining the execution order of the precharge processing in step S103 of FIG. 3, the control device (60) executes steps S105 to S117 in order according to the execution order. For example, in the example shown in FIG. 2, the sequence determining unit (65) determines the execution order as the second battery module (10B), the first battery module (10A), and the third battery module (10C). In this case, the nth precharge processing is performed according to the following sequence.

[0039] First, in the nth precharge process, steps S105 to S117 of FIG. 3 are executed in sequence for the second battery module (10B) in the first sequence. First, in step S105, the precharge process execution unit (67) turns ON the unit relay (30) of the second battery module (10B). Next, in step S107, the precharge relay (42) of the second battery module (10B) turns ON. In FIG. 5, for the second battery module (10B), the unit relay (30) is turned ON at time t11, and the precharge relay (42) is turned ON at time t12. Additionally, the order of the processing steps S105 and S107 may be reversed, and the unit relay (30) may be turned ON after the precharge relay (42) is turned ON. At time t12, since the unit relay (30) and the precharge relay (42) are turned ON, current flows through the precharge unit (40), thereby causing the main voltage V applied between a pair of output terminals (5) um This gradually increases.

[0040] After that, in step S109, the main voltage acquisition unit (61) is the main voltage V um It acquires the unit voltage. In addition, in step S111, the unit voltage acquisition unit (63) acquires the unit voltage V of the second battery module (10B). u2 It acquires the main voltage V. And, in step S113 of FIG. 3, the precharge processing execution unit (67) of FIG. 1 acquires the main voltage V um and, unit voltage V uS (Here, V u2 )'s difference(|V um -V u2 |) is the threshold V th Determines whether it is less than or equal to. Here, the main voltage V um and unit voltage V u2 The difference is the threshold V th If it is greater, return to step S109. Meanwhile, the main voltage V umand unit voltage V u2 The difference is the threshold V th If the result is less than or equal to the following, proceed to Step S115.

[0041] In step S115, the precharge processing execution unit (67) turns ON the main relay (20) for the second battery module (10B). Also, in step S117, the precharge processing execution unit (67) turns OFF the precharge relay (42). In FIG. 5, for the second battery module (10B), the main relay (20) is turned ON at time t13 and the precharge relay (42) is turned OFF at time t14. Here, the precharge processing for the second battery module (10B) is executed during time t11 to time t14.

[0042] In this way, after the precharge process is executed for the second battery module (10B) in the first order, the precharge process is performed for the first battery module (10A) in the second order by executing steps S105 to S117 of FIG. 3 in sequence. Here, the precharge process execution unit (67) executes the precharge process for the first battery module (10A) after the precharge process for the second battery module (10B) is completed (after time t14 of FIG. 5). At this time, the precharge relay (42) of the second battery module (10B) in the first order is OFF, and the main relay (20) and unit relay (30) are in the ON state. In this state, the precharge process for the first battery module (10A) is executed. In addition, since each of the processes of steps S105 to S117 for the first battery module (10A) is substantially the same as for the second battery module (10B), the explanation is omitted. In FIG. 5, for the first battery module (10A), the unit relay (30) is turned ON at time t21, which is later than time t14, and the precharge relay (42) is turned ON at time t22. Subsequently, during the period from time t22 to time t23, a precharge process for the first battery module (10A) is performed. And, the main voltage V um and unit voltage V u1 The difference is the threshold V th At time t23, the main relay (20) is turned ON, and at time t24, the precharge relay (42) is turned OFF. Here, the precharge process for the first battery module (10A) is performed during time t21 to time t24.

[0043] After precharge processing is performed on the second battery module (10B) of the first order and the first battery module (10A) of the second order, precharge processing is performed on the third battery module (10C) of the third order by sequentially executing steps S105 to S117. Here, precharge processing for the third battery module (10C) is performed while the precharge relays (42) of both the first battery module (10A) and the second battery module (10B) are OFF, and the main relay (20) and the unit relay (30) are ON. Additionally, since each of the processes of steps S105 to S117 for the third battery module (10C) is substantially the same as when for the second battery module (10B) and the first battery module (10A), the description here is omitted. In FIG. 5, for the third battery module (10C), the unit relay (30) is turned ON at time t31, which is later than time t24, and the precharge relay (42) is turned ON at time t32. Subsequently, precharge processing for the third battery module (10C) is performed during the period from time t32 to time t33. Then, the main voltage V um and unit voltage V u3 The difference is the threshold V th At time t33, the main relay (20) is turned ON, and at time t34, the precharge relay (42) is turned OFF. Here, the precharge processing for the third battery module (10C) is executed during time t31 to time t34. As described above, the precharge processing execution unit (67) independently executes precharge processing for each battery module (10A to 10C) according to the execution order determined by the sequence determination unit (65). After these precharge processing is executed, each battery module (10A to 10C) is connected to the load (100). By doing so, inrush current can be prevented from flowing into the load (100).

[0044] In the above embodiment, as shown in FIG. 1, the battery system (1) comprises a pair of output terminals (5) connected to a load (100), a plurality of battery modules (10) connected to the pair of output terminals (5) and arranged in parallel, and a control device (60). Each of the plurality of battery modules (10) comprises a battery unit (12) having a plurality of single cells (11) connected in series, a main relay (20) provided at the first end of the battery unit (12) (here, the end on the positive side), a unit relay (30) provided at the second end of the battery unit (12) (here, the end on the negative side), and a precharge unit (40) provided in parallel with the main relay (20). The precharge unit (40) is equipped with a pre-resistor (41) and a precharge relay (42) connected in series with the pre-resistor (41). The control device (60) is equipped with a precharge processing execution unit (67) that controls the connection of multiple battery modules (10) to the pair of output terminals (5) after performing precharge processing on one battery module (10) among the multiple battery modules (10) when multiple battery modules (10) are connected to the load (100) through a pair of output terminals (5). The precharge processing is performed by turning the main relay (20) OFF and turning the unit relay (30) and the precharge relay (42) ON for one battery module (10) to be targeted, and then the difference between the main voltage applied between the pair of output terminals (5) and the unit voltage of the battery unit (12) in one battery module (10) is a predetermined threshold V th (See FIG. 2) When the condition is less than or equal to the above, the main relay (20) of one battery module (10) is turned ON, and the precharge relay (42) is turned OFF. Furthermore, the control device (60) of this battery system (1) [determines] the elapsed time ΔT from the previous precharge processing of the battery module ranked 1st in the previous sequence (the first battery module (10A) in FIG. 2), which was the first to perform precharge processing when connected to the previous load (100).U1 Cooling time T C A time acquisition unit (64) for acquiring time and cooling time T C a predetermined standard time T D In the case of the following, a sequence determining unit (65) is further provided to determine the sequence of precharge processing so that precharge processing is not performed first on the battery module (first battery module (10A)) of the previous sequence when connecting to the next load (100).

[0045] In a general battery system, a very large current flows through the free resistor of the battery module ranked first, so the free resistor is prone to overheating. Furthermore, if the pre-charge process is performed again without allowing sufficient cooling time, the free resistor becomes very hot, thereby accelerating the degradation of the free resistor. In contrast, the battery system (1) according to the present embodiment has a time elapsed ΔT from the pre-charge process of the previous battery module ranked first (the first battery module (10A) in FIG. 2). u1 cooling time T C It is acquired as. And, this cooling time T C a reference time T D In the case below, it is determined that the pre-resistance (41) of the battery module (10A) in the previous sequence is at a high temperature, and the order of pre-charge processing is determined so that other battery modules (10B, 10C) become the next sequence. By doing so, since the pre-charge processing can be prevented from being repeated on the pre-resistance (41) at a high temperature, the uneven degradation of the pre-resistance (41) in multiple battery modules (10A to 10C) can be suppressed.

[0046] In addition, in the battery system (1) according to the present embodiment, the temperature of the free resistor (41) is not measured, and the elapsed time ΔT U1 to ΔT U3The order of precharge processing is determined based on [this]. By doing so, the following advantages are provided. First, in order to measure the temperature of the pre-resistance (41), it is necessary to install a temperature sensor in the battery module (10). In this case, since a large number of temperature sensors equal to the number of battery modules (10) are required, it causes an increase in component costs. On the other hand, elapsed time ΔT U1 to ΔT U3 The temperature can be measured solely by setting the timer within the control device (60). Additionally, in temperature measurement by a temperature sensor, it is difficult to accurately reflect the temperature inside the free resistor (41) because a delay occurs due to heat conduction from the free resistor (41) to the temperature sensor. On the other hand, since the amount of heat generated by the free resistor (41) due to the pre-charge process can be calculated, the time required for the free resistor to cool sufficiently (reference time T) D ) can also be easily calculated. For this reason, elapsed time ΔT U1 to ΔT U3 Control based on [this] allows for control at more accurate timing than control based on the detection result of a temperature sensor.

[0047] In addition, the control device (60) in this embodiment has a unit voltage V, which is the voltage of the battery unit (12), for each of the plurality of battery modules (10A to 10C). u1 to V u3 It is equipped with a unit voltage acquisition unit (63) for acquiring the unit voltage. And, the sequence determination unit (65) is provided with a plurality of unit voltages V acquired by the unit voltage acquisition unit (63). u1 to V u3 Based on this, a plurality of battery modules (10A to 10C) are arranged in descending order. Then, the sequence determining unit (65) determines that the first battery module in the arranged sequence is the battery module ranked first in the previous sequence, and also, cooling time T C a reference time T DIn the case below, a different battery module, distinct from the battery module ranked first in the previous sequence, is advanced to the battery module (10) where the pre-charge process is performed first when connected to the next load (100). First, by performing the pre-charge process for a plurality of battery modules (10) in order in descending order of unit voltage, the potential difference between the main voltage and the unit voltage between the plurality of battery modules (10) can be reduced. Therefore, the overcurrent that may occur due to the pre-charge process can be suppressed. Furthermore, if the cooling of the battery module ranked first in the previous sequence is insufficient, the order of the pre-charge process is changed. By doing so, the deterioration of the pre-resistance (41) can be suppressed more appropriately.

[0048] In addition, the time acquisition unit (64) in this embodiment has, for each of the plurality of battery modules (10A to 10C), the elapsed time ΔT from when the most recent precharge processing was first executed. u1 to ΔT u3 ...is acquired. And, the control device (60) obtains all elapsed time ΔT of the plurality of battery modules (10A to 10C). u1 to ΔT u3 This reference time T D In the case below, a predetermined error processing is executed. By doing so, the degradation of battery modules other than the battery module ranked first in the previous sequence can be appropriately suppressed. In addition, the error processing in this embodiment is a process that prohibits turning ON each of the main relay (20), unit relay (30), and precharge relay (42). By doing so, precharge processing can be prevented when all pre-resistors (41) are at a high temperature. As a result, thermal degradation of the pre-resistors (41) can be suppressed more reliably.

[0049] The foregoing has described one embodiment of the battery system disclosed herein. However, the above-described embodiment is not intended to limit the technology disclosed herein, and various modifications may be made.

[0050] For example, the error handling in the above-described embodiment prohibits turning ON each of the main relay (20), unit relay (30), and precharge relay (42). However, the specific details of the error handling are not limited to the above-described embodiment and can be appropriately changed according to the configuration or purpose of the battery system (1). For example, the error handling, among a plurality of battery modules (10A to 10C), elapsed time ΔT u1 to ΔT u3 The elapsed time of this longest battery module (in FIG. 2, the elapsed time ΔT of the second battery module (10B) u2 This is the reference time T D It may be a process that prohibits the initiation of pre-charge processing until it exceeds [a certain limit]. In this case, although there is a slight delay in the initiation of pre-charge processing, the thermal degradation of the pre-resistance (41) of the battery module other than the battery module ranked first in the previous sequence can be more appropriately suppressed.

[0051] In addition, error handling is performed during the elapsed time ΔT among the plurality of battery modules (10A to 10C). u1 to ΔT u3 The order of the precharge processing may be determined so that the precharge processing is performed first on this longest battery module (the second battery module (10B) in FIG. 2). In other words, in this error processing, the elapsed time ΔT u1 to ΔT u3 None of them are reference time T DIf it does not exceed [amount], pre-charge processing is initiated from the battery module (10) that has undergone the most cooling. When such error processing is set, pre-charge processing is initiated without delay, and the degradation of the pre-resistance (41) can be reduced as much as possible. Additionally, all of the above-described multiple error processing may be stored in the control device (60). In this case, it is preferable that the control device (60) be configured so that the user can select an appropriate error processing among the multiple error processing.

[0052] In addition, in the above-described embodiment, initially, the unit voltage V u1 to V u3 The order of precharge processing is set based on [this]. And, the elapsed time ΔT of the battery module (10A) in the previous sequence 1st position u1 (Cooling time T C Based on ), the order of the precharge process is changed so that the precharge process to the battery module (10) at high temperature is not performed first by the preresistor (41). However, the order of the precharge process is the unit voltage V of the battery modules (10A to 10C). u1 to V u3 Without considering elapsed time ΔT u1 to ΔT u3 It may be determined based solely on. That is, the sequence determining unit (65) determines the elapsed time ΔT of a plurality of battery modules (10A to 10C). u1 to ΔT u3 Based on this, the sequence number of the second and subsequent steps in the precharge process may also be determined. For example, as shown in FIG. 2, the elapsed time ΔT in the order of the second battery module (10B), the third battery module (10C), and the first battery module (10A). u1 to ΔT u3 In this case, pre-charge processing may be performed in this order. By doing so, each of the multiple battery modules (10A to 10C) can be cooled more efficiently.

[0053] In addition, in the above-described embodiment, the elapsed time ΔT of each of the plurality of battery modules (10A to 10C) u1 to ΔT u3 ...is being acquired. And, among these, the battery module (10) (the first battery module (10) in FIG. 2) with the shortest elapsed time is designated as the "battery module ranked first in the previous sequence," and the elapsed time of the battery module ranked first in the previous sequence (elapsed time ΔT of the first battery module (10)) u1 ) "Cooling time T C It is considered as 」. However, 「cooling time T C 」 refers to all elapsed time ΔT of a plurality of battery modules (10A to 10C). u1 to ΔT u3 It can be measured without acquiring it. For example, if the history of the battery module ranked first in the sequence so far is stored in the memory unit (69) of the control device (60), the battery module ranked first in the sequence of the previous sequence can be determined without measuring the elapsed time of all battery modules. Then, if the elapsed time of the battery module ranked first in the previous sequence determined based on this history is measured, the cooling time T C Only can be selectively measured.

[0054] In addition, in the above-described embodiment, as shown in step S10 of FIG. 4, the unit voltage V acquired in step S101 u1 , V u2 , V u3 Based on this, a plurality of battery modules (10A to 10C) are arranged in descending order. However, the order in which the plurality of battery modules are arranged based on unit voltage is not limited to descending order and may be ascending order. Even if the unit voltages are arranged in ascending order and pre-charge processing is performed in sequence, the potential difference between the main voltage and the unit voltage between the plurality of battery modules (10) can be reduced. As a result, overcurrent that may occur due to pre-charge processing can be suppressed.

[0055] The invention disclosed herein has been described in various ways. Unless specifically stated otherwise, the embodiments described herein do not limit the invention. Furthermore, the embodiments of the invention disclosed herein may be modified in various ways, and unless a particular problem arises, each component or each process mentioned herein may be appropriately omitted or appropriately combined.

[0056] As described above, the present specification includes the disclosures described in each of the following claims.

[0057] Paragraph 1:

[0058] A pair of output terminals connected to a load, and

[0059] A plurality of battery modules arranged in parallel and connected to the above pair of output terminals, and

[0060] controller

[0061] Equipped with,

[0062] The above plurality of battery modules are,

[0063] A battery unit having a plurality of single cells connected in series, and

[0064] A main relay provided at the end of the first side of the above battery unit, and

[0065] A unit relay provided at the end of the second side of the above-mentioned battery unit, and

[0066] A precharge unit provided in parallel with respect to the main relay above

[0067] Each is equipped with,

[0068] The above precharge unit is,

[0069] Free resistor and,

[0070] A precharge relay connected in series with the above pre-resistor

[0071] Equipped with,

[0072] The control device comprises a precharge processing execution unit that, when the plurality of battery modules are connected to the load through the pair of output terminals, controls the plurality of battery modules to be connected to the pair of output terminals after performing precharge processing on one of the plurality of battery modules at a time.

[0073] The above precharge processing is a process in which, for the one battery module of the target, the main relay is turned OFF and the unit relay and the precharge relay are turned ON, and then when the difference between the main voltage applied between the pair of output terminals and the unit voltage of the battery unit in the one battery module is less than or equal to a predetermined threshold, the main relay of the one battery module is turned ON and the precharge relay is turned OFF.

[0074] The above control device is,

[0075] Cooling time T, which is the elapsed time from the previous precharge treatment of the battery module ranked 1st in the previous sequence, where the precharge treatment was first executed during the connection to the aforementioned load in the previous sequence. C The time acquisition unit for acquiring, and

[0076] The above cooling time T C a predetermined standard time T D In the case below, a sequence determining unit that determines the sequence of the precharge process so that the precharge process is not executed first for the battery module ranked 1st in the previous sequence when connecting to the above load in the next session.

[0077] A battery system having additional

[0078] Paragraph 2:

[0079] The control device comprises, for each of the plurality of battery modules, a unit voltage acquisition unit that acquires a unit voltage which is the voltage of the battery unit, and

[0080] The above-mentioned sequence determining unit arranges the plurality of battery modules in ascending or descending order based on the plurality of unit voltages acquired by the unit voltage acquisition unit, and the first battery module in the arranged sequence is the battery module ranked first in the previous sequence, and also the cooling time T C a above reference time T D A battery system described in claim 1, wherein, in the case below, a different battery module different from the battery module of the previous sequence 1 is advanced to the battery module where the precharge processing is first performed when connected to the load in the next sequence.

[0081] Paragraph 3:

[0082] The battery system described in claim 1 or claim 2, wherein the time acquisition unit acquires, for each of the plurality of battery modules, the elapsed time from when the precharge treatment was first executed most recently.

[0083] Paragraph 4:

[0084] The above control device comprises all of the above elapsed times of the plurality of battery modules, the reference time T D A battery system described in Clause 3 that performs a predetermined error handling in the case of the following.

[0085] Paragraph 5:

[0086] The battery system described in claim 4, wherein the above error handling is a process that prohibits turning ON each of the main relay, the unit relay, and the precharge relay.

[0087] Paragraph 6:

[0088] The battery system described in claim 4, wherein the error handling described above is a process that prohibits the initiation of the precharge process until the elapsed time of the battery module with the longest elapsed time among the plurality of battery modules exceeds the reference time.

[0089] Paragraph 7:

[0090] The battery system described in claim 4, wherein the error processing above is a process for determining the order of the precharge processing such that the battery module with the longest elapsed time among the plurality of battery modules performs the precharge processing first when connected to the load in the next instance.

[0091] Paragraph 8:

[0092] A battery system described in any one of claims 1 to 7, wherein the above-described sequence determining unit determines the second or subsequent sequence number in the precharge processing based on the elapsed time of the plurality of battery modules. Explanation of the symbols

[0093] 1: Battery System 5: A pair of output terminals 10: Battery module 10A: 1st battery module 10B: Second battery module 10C: Third battery module 11: Single cell 12: Battery unit 20: Main Relay 30: Unit Relay 40: Precharge Unit 41: Free resistor 42: Precharge Relay 60: Control unit 61: Main voltage acquisition unit 63: Unit voltage acquisition section 64: Time Acquisition Department 65: Sequence number 67: Precharge processing execution section

Claims

Claim 1 A pair of output terminals connected to a load, a plurality of battery modules connected to the pair of output terminals and arranged in parallel, and a control device are provided. Each of the plurality of battery modules comprises a battery unit having a plurality of single cells connected in series, a main relay provided at the end of the first side of the battery unit, a unit relay provided at the end of the second side of the battery unit, and a precharge unit provided in parallel with respect to the main relay. Each of the precharge units comprises a pre-resistor and a precharge relay connected in series with the pre-resistor. The control device is provided with a precharge processing execution unit that controls the plurality of battery modules to be connected to the pair of output terminals after performing precharge processing on one of the plurality of battery modules at a time when the plurality of battery modules are connected to the load through the pair of output terminals. The precharge processing is performed by turning the main relay OFF and also turning the unit relay and the precharge relay ON for the target one battery module, and then the When the difference between the main voltage applied between the pair of output terminals and the unit voltage of the battery unit in the battery module is less than or equal to a predetermined threshold, the process of turning ON the main relay of the battery module and turning OFF the precharge relay is performed, and the control device has a cooling time T which is the elapsed time from the previous precharge process of the battery module ranked 1st in the previous sequence, where the precharge process was first executed during the previous connection to the load. C A time acquisition unit for acquiring , and the cooling time T C a predetermined standard time T D A battery system further comprising a sequence determining unit for determining the sequence of the precharge processing so that, in the case below, the precharge processing is not executed first for the battery module of the previous sequence 1st place when connected to the load of the next session. Claim 2 In claim 1, the control device comprises a unit voltage acquisition unit for each of the plurality of battery modules, which acquires a unit voltage that is the voltage of the battery unit, and the sequence determination unit arranges the plurality of battery modules in ascending or descending order based on the plurality of unit voltages acquired by the unit voltage acquisition unit, wherein the first battery module in the arranged sequence is the battery module ranked first in the previous sequence, and furthermore, the cooling time T C a above reference time T D A battery system that, in the case below, advances a different battery module, which is different from the battery module of the previous sequence 1, to the battery module where the precharge processing is first performed when connected to the load in the next sequence. Claim 3 A battery system according to claim 1, wherein the time acquisition unit acquires, for each of the plurality of battery modules, the elapsed time from when the precharge process was first executed most recently. Claim 4 In paragraph 3, the control device comprises all of the elapsed times of the plurality of battery modules being the reference time T D A battery system that performs a predetermined error handling in the case of the following. Claim 5 A battery system, wherein, in paragraph 4, the error handling is a process that prohibits turning ON each of the main relay, the unit relay, and the precharge relay. Claim 6 A battery system according to claim 4, wherein the error handling is a process that prohibits the initiation of the precharge process until the elapsed time of the battery module with the longest elapsed time among the plurality of battery modules exceeds the reference time. Claim 7 A battery system according to claim 4, wherein the error processing is a process for determining the order of the precharge processing such that the battery module with the longest elapsed time among the plurality of battery modules performs the precharge processing first when connected to the load in the next instance. Claim 8 A battery system according to claim 1, wherein the sequence determining unit determines the second or subsequent sequence number in the precharge process based on the elapsed time of the plurality of battery modules.

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