Combined Battery System

Abstract

Provided is a composite battery system that makes it possible to simplify the configuration thereof while ensuring the designed electric power storage capacity, and to identify a degraded lithium-ion battery and replace only the identified battery. Each of a plurality of composite units 12 that constitute the composite battery system 10 is provided with a plurality of main battery portions 20 and an auxiliary battery portion 30, the composite units 12 being connected to each other in series. Each of the plurality of main battery portions 20 is configured from a lithium-ion battery 22 and a switch 24, the plurality of main battery portions being connected to each other in parallel. The auxiliary battery portion 30 is configured from a lead storage battery 32 and is connected in parallel to the plurality of main battery portions 20. When the lithium-ion batteries 20 that constitute the plurality of main battery portions 20 are configured from conducting batteries and non-conducting batteries, an EMS 16 compares the total value of the capacity of the conducting batteries and the total value of the capacity of the non-conducting batteries, and switches on the switches 24 of the non-conducting batteries if the voltage of the batteries that have the smaller total value of capacity is higher than the voltage of the batteries that have the larger total value of capacity.

Description

[Technical field]

[0001] The present invention relates to a combined battery system using a plurality of combined units each composed of a lead-acid battery and a lithium-ion battery and connected in series with one another. [Background technology]

[0002] Conventionally, it is known that a combined battery in which a lead-acid battery and a lithium-ion battery are connected in parallel can increase the stored energy per weight and can improve low-temperature power performance in particular. Various technologies have been disclosed to improve the safety of the combined battery. Patent Document 1 discloses a combined battery system capable of maintaining safety even if a voltage sensor, a current sensor, a temperature sensor, or the like provided in a lithium-ion battery fails. On the other hand, regarding safety during deterioration of a secondary battery constituting an energy storage device, Patent Document 2 discloses a battery pack in which a diagnostic means diagnoses the deterioration degree or failure of each battery unit based on the voltage of a cell group or each cell, and Patent Document 3 discloses a charge / discharge control device that measures the current value of each cell during charging and controls a switching element to disconnect an abnormal cell detected based on the measured value from the parallel connection. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2017-208983 [Patent Document 2] Patent No. 5564561 [Patent Document 3] Patent Publication No. 2013-038884 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, even if a voltage sensor, current sensor, temperature sensor, etc. provided in a lithium-ion battery fails, if at least one of overcharging and over-discharging is detected by a voltage detector for detecting the voltage value of each combined battery, a unit disconnect switch is operated to electrically disconnect multiple combined batteries included in the same combined battery unit as the combined battery equipped with the voltage detector. However, there is a problem in that no consideration is given to identifying a deteriorated lithium-ion battery and replacing only that battery.

[0005] In addition, in Patent Document 2, the deterioration level of each battery unit is diagnosed based on the ratio between the voltage measurement value when the second current control element is turned off and the voltage measurement value when the second current control element is turned on while the first current control element is turned off, so there is a problem that the number of switches increases and the circuit configuration becomes complicated. Furthermore, there is a problem that no consideration is given to identifying the deteriorated battery after diagnosing the deterioration level of each battery unit and replacing only that battery. Furthermore, in Patent Document 3, all five single cells are connected to the charge / discharge path via the current measurement unit during charging, and are connected to the charge / discharge path without the current measurement unit during discharging, so there is a problem that the number of switches increases and the circuit configuration becomes complicated.

[0006] The present invention has been made in consideration of these problems in the conventional technology, and an object of the present invention is to provide a combined battery system that has a simple configuration while ensuring the specified storage capacity, and that is capable of identifying degraded lithium-ion batteries and replacing only those batteries. Another object of the present invention is to provide a combined battery system that, in addition to the above-mentioned objects, maintains safety equal to or greater than that of conventional batteries, utilizes resources effectively, expands applications, and increases scalability. [Means for solving the problem]

[0007] In order to achieve the above-mentioned objective, the inventor conducted extensive research and discovered that by configuring multiple main battery units with a basic number of main battery units set based on the specifications and a surplus number of main battery units set as a surplus to the basic number of connections, and by calculating the number of connections of degraded batteries among the multiple main battery units, and when the number of connections of degraded batteries becomes equal to the surplus number of connections, a signal is sent to an external device requesting replacement of the degraded batteries, it is possible to replace only the degraded lithium-ion batteries while maintaining the storage capacity specified.

[0008] The inventors also discovered that by defining deterioration of a lithium ion battery as a result of repeated charging and discharging of multiple main battery units, such that the measured current value of each lithium ion battery in the multiple main battery units deviates from a specified range, it is possible to simplify the configuration and identify deteriorated lithium ion batteries, and thus arrived at the present invention.

[0009] That is, a first aspect of the present invention includes a plurality of composite units each including a lithium ion battery and a switch for electrically connecting or disconnecting the lithium ion battery, and connected in parallel with each other; and an auxiliary battery unit each including a lead-acid battery and connected in parallel with the plurality of main battery units, and connected in series with each other; an HV unit that directly or indirectly obtains measured values ​​of voltage, current and temperature during charging and discharging of the lithium ion battery; an EMS that, when a lithium ion battery that has deteriorated due to repeated charging and discharging of the plurality of main battery units is recognized as a deteriorated battery, turns off a switch connected to the deteriorated battery and notifies an external device of information identifying the deteriorated battery; and and a housing for housing the lithium-ion battery, wherein the EMS recognizes the lithium-ion battery as a degraded battery when the measured value of at least one of the currents during charging and discharging deviates from a predetermined range, and when the lithium-ion batteries constituting the multiple main battery units in at least one of the multiple composite units are composed of one or more powered batteries connected to a switch in an on state and one or more non-powered batteries connected to a switch in an off state, the EMS compares the sum of the capacities of the powered batteries with the sum of the capacities of the non-powered batteries, and turns on the off switch of the non-powered batteries when the voltage of the battery with the smaller sum of the capacities is higher than the voltage of the battery with the larger sum of the capacities.

[0011] In addition, the present invention 2The device has a configuration including a plurality of main battery units each composed of a lithium ion battery and a switch for electrically connecting or disconnecting the lithium ion battery and connected in parallel with each other, and a plurality of composite units each comprising an auxiliary battery unit composed of a lead acid battery and connected in parallel with the plurality of main battery units and connected in series with each other, an HV unit that directly or indirectly obtains measured values ​​of voltage, current and temperature during charging and discharging of the lithium ion battery, an EMS that, when it recognizes a lithium ion battery that has deteriorated as a result of repeated charging and discharging of the plurality of main battery units as a deteriorated battery, turns off a switch connected to the deteriorated battery and notifies an external device of information identifying the deteriorated battery, and a housing that houses the plurality of composite units and the HV unit, and the plurality of main battery units are connected in series with each other based on the basic number of connections set for each of the plurality of composite units. The present invention provides a combined battery system which is composed of a battery section and main battery sections with a number of surplus connections set as a surplus over the basic connection number, and for each of a plurality of composite units, the number of basic connections is four or more and the number of surplus connections is one or more, and when the measured value of at least one of the currents during charging and discharging deviates from a predetermined range, the EMS recognizes the lithium-ion battery as a degraded battery, and, among the measured values ​​obtained by simultaneously measuring the current of each of the lithium-ion batteries constituting each of the plurality of main battery sections during charging and discharging, if there is a lithium-ion battery among the plurality of main battery sections that the EMS recognizes as a degraded battery, the measured value of the lithium-ion battery in question is excluded, and further, the average value of the remaining measured values ​​is calculated, excluding the largest measured value and the smallest measured value from the remaining measured values.

[0012] Furthermore, the present invention Type 2 In this embodiment, it is preferable that the EMS calculates the number of connections of degraded batteries among the multiple main battery sections for each of the multiple composite units, and when the number of connections of degraded batteries becomes equal to the number of surplus connections, sends a signal to an external device requesting replacement of the degraded batteries. Furthermore, the first aspect of the present invention 、 No. 2In this embodiment, the auxiliary battery unit further includes an ammeter that measures the current flowing through the lead-acid battery, an auxiliary switch that electrically connects or disconnects the lead-acid battery, and an auxiliary BMS, and the auxiliary BMS preferably turns the auxiliary switch on and off based on the measured value of the current flowing through the lead-acid battery, and notifies an external device of the measured value of the current flowing through the lead-acid battery via the HV unit and the EMS.

[0013] Furthermore, the first aspect of the present invention 、 No. 2 In this embodiment, it is preferable that the auxiliary battery section further includes a fuse that cuts off current flowing to the lead-acid battery when an overcurrent flows through the lead-acid battery. It is preferable that each of the multiple main battery units is equipped with a BMS, which measures the voltage, current and temperature of the lithium-ion battery, calculates the SOC and SOH based on the voltage, current and temperature, and notifies an external device of the measured values ​​of voltage, current and temperature as well as the calculated SOC and SOH via the HV unit and EMS. It is preferable that the HV unit measures the voltage, current and temperature of the lithium-ion battery, calculates the SOC and SOH based on the voltage, current and temperature, and notifies an external device via the EMS of the measured values ​​of voltage, current and temperature as well as the calculated SOC and SOH.

[0014] Furthermore, the first aspect of the present invention 、 No. 2 In this embodiment, it is preferable that the EMS further includes a thermometer that measures the temperature inside the housing, and a heating and cooling device that changes the temperature inside the housing, and that the EMS turns on and off at least one of the heating and cooling device and the switch based on the temperature of the lithium-ion battery and the measurement value of the thermometer, and notifies an external device of the temperature of the lithium-ion battery and the measurement value of the thermometer. Furthermore, it is preferable that the housing has a fire extinguisher that automatically detects and extinguishes a flame that occurs inside the housing, and that the EMS notifies an external device of the operation of the fire extinguisher when the fire extinguisher is activated. It is preferable that the housing further includes a hydrogen gas sensor that measures the concentration of hydrogen gas inside the housing and a fan that ventilates the air inside the housing, and that the auxiliary battery unit further includes an auxiliary switch that electrically connects or disconnects the lead-acid battery, and that the EMS turns on and off at least one of the fan and the auxiliary switch based on the measured value of the hydrogen gas concentration, and notifies an external device of the measured value of the hydrogen gas concentration.

[0015] Furthermore, the first aspect of the present invention 、 No. 2 In this embodiment, it is preferable that the EMS further includes an organic gas sensor that measures the concentration of the organic gas inside the housing, and a fan that ventilates the air inside the housing, and that the EMS turns on and off at least one of the fan and the switch based on the measured value of the organic gas concentration, and notifies an external device of the measured value of the organic gas concentration. Furthermore, it is preferable that the housing has a PCS that is arranged inside or outside the housing and converts the discharge power from the lithium ion battery and the lead acid battery to an external device from DC to AC, and converts the charging power from the external device to the lithium ion battery and the lead acid battery from AC to DC. It is preferable that the EMS turns the switch on and off based on the measured voltage value and notifies an external device of the measured voltage value, and that the EMS receives notifications from the HV units housed in each of the multiple housings. The predetermined range is preferably 70 to 130% of both the average value of the measured value during charging and the average value of the measured value during discharging. Effect of the Invention

[0016] According to the present invention, the configuration can be simplified while ensuring the specified storage capacity, and it is possible to identify a deteriorated lithium ion battery and replace only that battery. Furthermore, according to the present invention, in addition to the above effects, it is possible to maintain safety equal to or greater than that of the prior art, to utilize resources effectively, to expand applications, and to increase scalability. [Brief description of the drawings]

[0017] [Figure 1]FIG. 1 is a block diagram showing a combined battery system of the present invention. [Diagram 2] 2 is a block diagram showing a modified example of the auxiliary battery unit constituting the combined battery system of FIG. 1. FIG. [Diagram 3] 2 is a block diagram showing a specific module configuration of a main battery section that constitutes the combined battery system of FIG. 1. FIG. [Figure 4] 4 is a block diagram showing another specific module configuration of the main battery unit in FIG. 3. [Diagram 5] 2 is a block diagram showing a specific module configuration of an auxiliary battery section that constitutes the combined battery system of FIG. 1. FIG. [Figure 6] 3 is a block diagram showing a specific module configuration of a modified example of the auxiliary battery unit in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a combined battery system according to the present invention; FIG.

[0019] The first aspect of the present invention 、 No. 2 The combined battery system 10 in this embodiment has a plurality of combined units 12, an HV section 14, an EMS 16, and a housing 18. Each of the multiple combined units 12 includes a plurality of main battery sections 20 and auxiliary battery sections 30, which are connected in series with each other. Each of the multiple main battery sections 20 includes a lithium ion battery 22 and a switch 24, which are connected in parallel with each other. The switch 24 electrically connects or disconnects the lithium ion battery 22. The auxiliary battery section 30 includes a lead storage battery 32, which is connected in parallel with the multiple main battery sections 20.

[0020] The HV section 14 directly or indirectly acquires measured values ​​of voltage, current and temperature during charging and discharging of the lithium ion battery 22. When the EMS 16 recognizes a lithium ion battery 22 that has deteriorated due to repeated charging and discharging of the multiple main battery sections 20 as a deteriorated battery, it turns off the switch 24 connected to the deteriorated battery and notifies the external device 40 of information identifying the deteriorated battery. The housing 18 houses the multiple composite units 12 and the HV section 14.

[0021] That is, the entire composite units 12 are configured by connecting M main battery units 20 in parallel and N main battery units 20 in series in a matrix, each of which is configured by connecting a lithium ion battery 22 and a switch 24 in series with each other, and then connecting an auxiliary battery unit 30 configured by a lead storage battery 32 in parallel to each of the N main battery units 20 connected in series. A degraded battery refers to a lithium ion battery 22 whose internal resistance during charging and discharging gradually increases with repeated charging and discharging, or suddenly decreases with an internal short circuit, and the measured current falls outside a predetermined range. Information identifying a degraded battery includes the serial number of the lithium ion battery 22 whose measured current falls outside the predetermined range, a combination of the ordinal number of the parallel connection (the number out of M batteries) and the ordinal number of the series connection (the number out of N batteries) in a matrix-connected state, and the like. The HV unit 14 and the EMS 16 are configured by electric circuits and include a CPU as necessary.

[0022] Next, a method for switching on the new lithium ion battery after replacing the deteriorated battery with a new lithium ion battery, which is applied to the combined battery system 10 of the first embodiment of the present invention, will be described. The EMS 16 recognizes the lithium ion battery as a deteriorated battery when at least one of the measured values ​​of the current during charging and discharging deviates from a predetermined range. In at least one of the multiple composite units 12, the lithium ion battery 22 constituting the multiple main battery units 20 is composed of one or more energized batteries and the remaining one or more non-energized batteries, and the energized battery is connected to the switch 24 in the ON state, and the non-energized battery is connected to the switch 24 in the OFF state. In this case, the EMS 16 compares the total value of the energized batteries with the total value of the non-energized batteries, and turns on the switch 24 in the OFF state of the non-energized battery when the voltage of the battery with the smaller total value of the capacities is higher than the voltage of the battery with the larger total value of the capacities. The predetermined range may be 70 to 130% of both the average value of the measured values ​​during charging and the average value of the measured values ​​during discharging.

[0023] For example, if the sum of the capacities of the energized battery is smaller, switch 24, which has the non-energized battery in an off state, is turned on when the voltage of the energized battery is higher than that of the non-energized battery, i.e., during the period from when the voltages of the energized battery and the battery are equal to full charge if the energized battery is being charged, or during the period from when the energized battery is fully charged to when the battery is being discharged and the battery voltages are equal to full charge if the energized battery is being discharged. As a result, when switch 24 is turned on, an inrush current flows from the energized battery, which has a smaller sum of the capacities, to the non-energized battery, which has a larger sum of the capacities, so the C rate on the inrush current flow side is smaller than when current flows in the opposite direction.

[0024] Conversely, if the total value of the capacities of the non-powered batteries is smaller, switch 24, which has the non-powered batteries in an off state, is turned on when the voltage of the non-powered batteries is higher than that of the powered batteries, i.e., during the period from full discharge until the voltages of the two batteries become equal if the powered battery is being charged, or during the period from when the voltages of the two batteries become equal until the powered battery is being discharged. As a result, when switch 24 is turned on, an inrush current flows from the non-powered battery, which has a smaller total value of the capacities, to the powered battery, which has a larger total value of the capacities, so the C rate on the inrush current side is smaller than when current flows in the opposite direction.

[0025] The difference between the two voltages is preferably 10 to 100 mV. If the difference between the two voltages is less than 10 mV, there is a risk of current flowing in the reverse direction when the voltage is unstable. If the difference between the two voltages exceeds 100 mV, the magnitude of the inrush current becomes too large. The C rate is the ratio of the charge / discharge current value to the battery capacity, and 1 C represents the current value when the battery goes from a fully charged state to a fully discharged state in one hour.

[0026] With this configuration, the combined battery system of the present invention can reduce damage to the lithium-ion batteries caused by inrush current when the switch is turned on, thereby extending the life of the lithium-ion batteries and making effective use of resources.

[0027] next, For reference: The criteria for determining whether a battery is degraded, which are applied to the combined battery system 10, will be described below. The main battery units 20 are composed of a basic number of main battery units set based on the specifications for each of the multiple composite units 12 and a surplus number of main battery units set as a surplus to the basic number of connections. The basic number of connections for each of the multiple composite units 12 may be two or more, but is preferably three or more, and more preferably four or more. The surplus number of connections may be one or more, but is preferably two or more, and more preferably three or more. When the measured values ​​of the current during both charging and discharging deviate from a predetermined range, the EMS 16 may recognize the lithium ion battery as a deteriorated battery and calculate the average values ​​of the measured values ​​obtained by simultaneously measuring the current during charging and discharging of each of the lithium ion batteries 22 constituting each of the main battery units 20. The predetermined range may be 70 to 130% of both the average value of the measured values ​​during charging and the average value of the measured values ​​during discharging.

[0028] For example, when the number of basic connections is eight and the number of surplus connections is two for each of the multiple composite units 12, each composite unit 12 is configured by connecting in parallel the first to eighth lithium ion batteries 22 connected in parallel based on the specifications and the ninth and tenth lithium ion batteries 22 connected in parallel as surplus batteries. In one of the N composite units 12 connected in series, the measured values ​​of the currents measured simultaneously during charging and discharging of each lithium ion battery 22 happen to be the same, for example, 1.2 A, 14.0 A, 10.0 A, 10.1 A, 10.2 A, 10.3 A, 10.4 A, 10.5 A, 10.6 A, and 10.7 A. In this case, the average measurement value is 9.8 A, and the range of 70 to 130% of the average measurement value is 6.86 to 12.74 A, so the first measurement value of 1.2 A and the second measurement value of 14.0 A are outside this range both during charging and discharging.

[0029] Therefore, the first and second lithium ion batteries are recognized and counted as degraded batteries. In this case, the EMS 16 turns off the switch 24 connected to the degraded battery and notifies the external device 40 of information identifying the degraded battery. The above is the specific processing content executed in one of the N composite units 12, and the EMS 16 executes the same for the other composite units. If the measured values ​​in both the charging and discharging states are less than 70% of the respective average values, it can be determined that the internal resistance is too high and that the battery is completely degraded. If the measured values ​​are more than 130% of the respective average values, it is considered that there is a sign of an internal short circuit and therefore it can be determined that the battery is completely degraded.

[0030] With this configuration, For reference: Compared to the case in which abnormal cells are detected only while the energy storage device is being charged, as in Patent Document 3, this combined battery system can reduce the possibility of erroneous judgment due to measurement abnormalities, thereby simplifying the configuration and enabling degraded lithium-ion batteries to be properly identified.

[0031] Next, the present invention 2 Another criterion for determining whether a battery is degraded that is applied to the combined battery system 10 of this embodiment will be described. The main battery units 20 are composed of a basic number of main battery units set based on the specifications for each of the multiple composite units 12 and a surplus number of main battery units set as a surplus to the basic number of connections. For each of the multiple composite units 12, the basic number of connections may be four or more, but is preferably five or more, and more preferably six or more. The surplus number of connections may be one or more, but is preferably two or more, and more preferably three or more. When the measured value of at least one of the currents during charging and discharging deviates from a predetermined range, the EMS 16 recognizes the lithium ion battery as a deteriorated battery, and, among the measured values ​​obtained by simultaneously measuring the currents of the lithium ion batteries 22 constituting each of the multiple main battery units 20 in at least one of the charging and discharging states, if the EMS 16 recognizes a lithium ion battery as a deteriorated battery among the multiple main battery units 20, the measured value of the corresponding lithium ion battery may be excluded, and further, the average value of the remaining measured values ​​may be calculated by excluding one measured value with the largest magnitude and one measured value with the smallest magnitude from the remaining measured values. The predetermined range may be 70 to 130% of both the average value of the measured value during charging and the average value of the measured value during discharging.

[0032] For example, if the number of basic connections is eight and the number of surplus connections is two for each of the multiple composite units 12, each composite unit 12 is configured by connecting in parallel the first to eighth lithium ion batteries 22 connected in parallel based on the specifications and the ninth and tenth lithium ion batteries 22 connected in parallel as surplus batteries. In one of the N composite units 12 connected in series, the measured values ​​of the currents of the lithium ion batteries 22 measured simultaneously during charging and discharging happen to be the same, for example, 1.2 A, 14.0 A, 10.0 A, 10.1 A, 10.2 A, 10.3 A, 10.4 A, 10.5 A, 10.6 A, and 10.7 A, and the first lithium ion battery with the measured value of 1.2 A is the lithium ion battery recognized by the EMS 16 as a deteriorated battery. In this case, first excluding 1.2A, then excluding 14.0A and 10.0A, the average of the remaining seven measurement values ​​is 10.4A, and the range of 70 to 130% of the average measurement value is 7.28 to 13.52A, so the second measurement value of 14.0A is outside this range both during charging and discharging.

[0033] Therefore, the second lithium ion battery is recognized as a new degraded battery and counted. In this case, the EMS 16 turns off the switch 24 connected to the degraded battery and notifies the external device 40 of information identifying the degraded battery. The above is the specific processing content executed in one of the N composite units 12, and the EMS 16 executes the same for the other composite units. If the measured value in at least one of the charging and discharging states is less than 70% of the respective average values, it can be determined that the internal resistance is too high and that the battery is completely degraded. If the measured value is more than 130% of the respective average values, it is considered that there is a sign of an internal short circuit and therefore it can be determined that the battery is completely degraded.

[0034] By adopting such a configuration, the combined battery system of the present invention can reduce the possibility of erroneous judgment due to measurement abnormalities compared to the case of simply calculating the average current value of the parallel-connected single cells as in Patent Document 3, thereby simplifying the configuration and enabling degraded lithium-ion batteries to be appropriately identified.

[0035] Next, the conditions for replacing a deteriorated battery will be described. The EMS 16 calculates the number of degraded batteries connected among the multiple main battery sections 20 for each of the multiple composite units 12, and when the number of degraded batteries connected becomes equal to the number of surplus connections, it sends a signal to the external device 40 requesting replacement of the degraded battery.

[0036] With this configuration, the combined battery system of the present invention can maintain safety even if the lithium ion battery deteriorates.

[0037] Next, the configuration of the auxiliary battery section will be described. The auxiliary battery unit 30 may further include an ammeter 34, an auxiliary switch 36, and an auxiliary BMS 38. In this case, the ammeter 34 measures the current flowing through the lead-acid battery 32. The auxiliary switch 36 electrically connects or disconnects the lead-acid battery 32. The auxiliary BMS 38 turns the auxiliary switch 36 on and off based on the measured value of the current flowing through the lead-acid battery 32, and notifies the external device 40 of the measured value of the current flowing through the lead-acid battery 32 via the HV unit 14 and the EMS 16.

[0038] With this configuration, the combined battery system of the present invention can maintain safety even if an overcurrent flows through the lead-acid battery.

[0039] Next, a modified example of the auxiliary battery unit will be described. Fig. 2 is a block diagram showing a modified example of the auxiliary battery unit constituting the combined battery system of Fig. 1. The auxiliary battery unit 30a of the present invention has the same configuration as the auxiliary battery unit 30 except that it has a fuse 50 instead of the ammeter 34 and the auxiliary switch 36 and does not have the auxiliary BMS 38, so a description of the same components will be omitted. The auxiliary battery section 30 may further include a fuse 50. In this case, the fuse 50 cuts off the current flowing through the lead-acid battery 32 when an overcurrent flows through the lead-acid battery 32.

[0040] With this configuration, the combined battery system of the present invention can maintain safety even if an overcurrent flows through the lead-acid battery.

[0041] Next, the functions of the BMS will be described. Each of the multiple main battery units 20 may include a BMS 26. In this case, the BMS 26 measures the voltage, current, and temperature of the lithium-ion batteries 22, calculates the SOC and SOH based on the voltage, current, and temperature, and notifies the external device 40 of the measured values ​​of the voltage, current, and temperature as well as the calculated values ​​of the SOC and SOH via the HV unit 14 and the EMS 16.

[0042] With this configuration, the combined battery system of the present invention can use the BMS that comes with the lithium-ion batteries as is, thereby making effective use of resources.

[0043] Next, we will explain the case where the BMS function is incorporated into the HV unit. The HV unit 14 may measure the voltage, current, and temperature of the lithium-ion battery 22, calculate the SOC and SOH based on the voltage, current, and temperature, and notify the external device 40 via the EMS 16 of the measured values ​​of the voltage, current, and temperature as well as the calculated SOC and SOH.

[0044] With this configuration, the combined battery system of the present invention integrates the functions of the BMS into the HV section, making it possible to simplify the configuration of the combined battery system.

[0045] Next, temperature control inside the housing will be described. The combined battery system 10 may further include a thermometer 52 and a heating and cooling device 54. In this case, the thermometer 52 measures the temperature inside the housing 18. The heating and cooling device 54 changes the temperature inside the housing 18. The EMS 16 turns on and off at least one of the heating and cooling device 54 and the switch 24 based on the temperature of the lithium-ion battery 22 and the measurement value of the thermometer 52, and notifies the external device 40 of the temperature of the lithium-ion battery 22 and the measurement value of the thermometer 52.

[0046] With this configuration, the combined battery system of the present invention controls the temperature of the lithium ion battery and the temperature inside the casing within a safe range, thereby maintaining safety.

[0047] Next, fire prevention measures for the inside of the housing will be described. The combined battery system 10 may further include a fire extinguisher 56. In this case, the fire extinguisher 56 automatically detects and extinguishes a flame occurring inside the housing 18. When the fire extinguisher 56 is activated, the EMS 16 notifies the external device 40 of the activation of the fire extinguisher 56.

[0048] With this configuration, the combined battery system of the present invention can maintain safety even if a fire breaks out inside the casing due to a lightning strike, a wiring short circuit, or the like.

[0049] Next, measures against hydrogen gas inside the housing will be described. The combined battery system 10 may further include a hydrogen gas sensor 58 and a fan 60, and the auxiliary battery section 30 may further include an auxiliary switch 36. In this case, the hydrogen gas sensor 58 measures the concentration of hydrogen gas inside the housing 18. The fan 60 ventilates the air inside the housing 18. The auxiliary switch 36 electrically connects or disconnects the lead-acid battery 32. The EMS 16 turns on and off at least one of the fan 60 and the switch 24 based on the measured value of the hydrogen gas concentration, and notifies the external device 40 of the measured value of the hydrogen gas concentration.

[0050] With this configuration, the combined battery system of the present invention can maintain safety even if a large amount of hydrogen gas is generated from the lead-acid battery due to overcharging of the lead-acid battery, for example.

[0051] Next, measures against organic gases inside the housing will be described. The combined battery system 10 may further include an organic gas sensor 62 and a fan 60. In this case, the organic gas sensor 62 measures the concentration of the organic gas inside the housing 18. The fan 60 ventilates the air inside the housing 18. The EMS 16 turns on and off at least one of the fan 60 and the switch 24 based on the measured value of the organic gas concentration, and notifies the external device 40 of the measured value of the organic gas concentration.

[0052] With this configuration, the combined battery system of the present invention can maintain safety even if a large amount of electrolyte leaks from the lithium ion battery due to deterioration of the lithium ion battery or the like.

[0053] Next, a description will be given of the broadening of the uses and the enhancement of the scalability of the combined battery system of the present invention. The combined battery system 10 may further include a PCS 64. In that case, the PCS 64 is disposed inside or outside the housing 18, and converts the discharge power from the lithium ion battery 22 and the lead storage battery 32 to the external device 40 from DC to AC, and converts the charging power from the external device 40 to the lithium ion battery 22 and the lead storage battery 32 from AC to DC.

[0054] With such a configuration, the combined battery system of the present invention can broaden the range of uses for the combined battery system.

[0055] The EMS 16 may turn on and off the switch 24 based on the measured voltage value, and may also notify the external device 40 of the measured voltage value. The EMS 16 may also receive notifications from the HV units 14 housed in each of the multiple housings 18.

[0056] With such a configuration, the combined battery system of the present invention can improve the expandability of the combined battery system.

[0057] Next, a specific module configuration of the main battery section and the auxiliary battery section will be described. FIG. 3 is a block diagram showing a specific module configuration of the main battery section constituting the combined battery system of FIG. 1. The main battery section 20a of the present invention has the same configuration as the main battery section 20 except that it has a plurality of lithium ion battery modules 22m connected in series with each other instead of the lithium ion battery 22, so a description of the same components will be omitted. FIG. 4 is a block diagram showing another specific module configuration of the main battery section of FIG. 3. The main battery section 20b of the present invention has a plurality of lithium ion battery modules 22m connected in series with each other instead of the lithium ion battery 22 with respect to the main battery section 20, has a switch module 24m corresponding to each lithium ion battery module 22m instead of the switch 24, and has a BMS module 26m corresponding to each lithium ion battery module 22m instead of the BMS 26.

[0058] 5 is a block diagram showing a specific module configuration of the auxiliary battery unit constituting the combined battery system of FIG. 1. The auxiliary battery unit 30b of the present invention has the same configuration as the auxiliary battery unit 30 except that it has a plurality of lead-acid battery modules 32m connected in series with each other instead of the lead-acid battery 32, so a description of the same components will be omitted. FIG. 6 is a block diagram showing a specific module configuration of a modified example of the auxiliary battery unit of FIG. 2. The auxiliary battery unit 30c of the present invention has the same configuration as the auxiliary battery unit 30a except that it has a plurality of lead-acid battery modules 32m connected in series with each other instead of the lead-acid battery 32, so a description of the same components will be omitted.

[0059] As an example, the configuration of a combined battery system A will be described. In the combined battery system A, the multiple combined units 12 may be two combined units 12 connected in series with each other. The lithium ion battery 22 may be 17 lithium ion battery modules 22m connected in series with each other, each having a battery capacity of 5.63 kWh and an operating voltage of about 24 V. The lead acid battery 32 may be 32 lead acid battery modules 32m connected in series with each other, each having a battery capacity of 0.36 kWh and an operating voltage of about 12.75 V.

[0060] In the combined battery system A, the lithium-ion battery module 22m is AS-OP-8S manufactured by BYD, and the lithium-ion battery 22 has a battery capacity of 95.7 kWh and an operating voltage of about 408 V. The lead-acid battery module 32m is 33-12 manufactured by LCPA, and the lead-acid battery 32 has a battery capacity of 11.5 kWh and an operating voltage of about 408 V. When the number of basic connections of the main battery part 20 is two and the number of redundant connections is one, each combined unit 12 has a battery capacity of 202.9 kWh for the basic connection number and a battery capacity of 298.6 kWh including the redundant connection number. When the number of series connections of the combined units 12 is two, the combined units 12 as a whole have a battery capacity of 405.8 kWh for the basic connection number and a battery capacity of 597.2 kWh including the redundant connection number, and an operating voltage of about 816 V.

[0061] As another example, the configuration of a combined battery system B will be described. In the combined battery system B, the multiple combined units 12 may be four combined units 12 connected in series with each other. The lithium ion battery 22 may be two lithium ion battery modules 22m connected in series with each other, each having a battery capacity of 26.73 kWh and an operating voltage of about 150 V. The lead acid battery 32 may be 24 lead acid battery modules 32m connected in series with each other, each having a battery capacity of 0.36 kWh and an operating voltage of about 12.75 V.

[0062] In the combined battery system B, the lithium-ion battery module 22m is an e-BUS battery L173TB2, and the lithium-ion battery 22 has a battery capacity of 53.46 kWh and an operating voltage of about 300 V. The lead-acid battery module 32m is an LCPA 33-12, and the lead-acid battery 32 has a battery capacity of 8.64 kWh and an operating voltage of about 306 mV. When the number of basic connections of the main battery section 20 is two and the number of redundant connections is one, each combined unit 12 has a battery capacity of 115.6 kWh for the basic connection number and a battery capacity of 169.0 kWh including the redundant connection number. When the number of series connections of the combined units 12 is four, the combined units 12 as a whole have a battery capacity of 462.2 kWh for the basic connection number and a battery capacity of 676.1 kWh including the redundant connection number, and an operating voltage of about 1200 V.

[0063] In the combined battery systems A and B, a battery management unit (hereinafter referred to as BMU) is mounted inside the lithium-ion battery module 22m, and if a 12V control power supply is required to drive the BMU, it is connected. In this case, the startup procedure for the combined battery systems A and B is as follows: first, the BMS software is modified in advance so that the lithium-ion battery module 22m is in a state in which it can be charged and discharged even if an external voltage is applied, then the switch connected between the lithium-ion battery module 22m and the 12V control power supply is turned on, and then the contactor of the lithium-ion battery module 22m is turned on to make the lithium-ion battery module 22m in a state in which it can be charged and discharged. The combined battery system of the present invention is basically configured as described above.

[0064] Although the combined battery system of the present invention has been described in detail above, the present invention is not limited to the above description, and various improvements and modifications may be made without departing from the spirit and scope of the present invention. [Industrial Applicability]

[0065] The combined battery system of the present invention has the advantages of simplifying the configuration while ensuring the specified storage capacity, and being able to identify and replace only degraded lithium-ion batteries. In addition, it has the advantages of maintaining safety at least equal to that of conventional systems, making effective use of resources, expanding applications, and increasing scalability, making it industrially useful. [Explanation of symbols]

[0066] 10 Combined Battery System 12 Composite Unit 14 HV section 16 EMS 18. Cabinet 20, 20a, 20b Main battery section 22 Lithium-ion battery 22m Lithium-ion battery module 24 Switch 24m Switch Module 26 BMS 26m BMS module 30, 30a, 30b, 30c Auxiliary battery section 32 Lead acid battery 32m Lead-acid battery module 34 Ammeter 36 Auxiliary Switch 38 Auxiliary BMS 40 External equipment 50 Fuse 52 Thermometer 54 Heating and cooling equipment 56 Fire extinguisher 58 Hydrogen gas sensor 60 Fans 62 Organic Gas Sensor 64 PCS

Claims

1. a plurality of main battery units each including a lithium ion battery and a switch for electrically connecting or disconnecting the lithium ion battery, and connected in parallel with each other; and a plurality of composite units each including an auxiliary battery unit each including a lead-acid battery, and connected in parallel with the plurality of main battery units, and connected in series with each other; an HV unit that directly or indirectly obtains measurements of voltage, current and temperature during charging and discharging of the lithium ion battery; an EMS that, when recognizing a lithium ion battery that has deteriorated due to repeated charging and discharging of the plurality of main battery units as a deteriorated battery, turns off a switch connected to the deteriorated battery and notifies an external device of information identifying the deteriorated battery; a housing that houses the plurality of composite units and the HV section, The EMS recognizes the lithium ion battery as a deteriorated battery when a measured value of at least one of the currents during charging and discharging deviates from a predetermined range; In at least one of the multiple composite units, when the lithium ion batteries constituting the multiple main battery sections are composed of one or more powered batteries connected to a switch in an on state and one or more non-powered batteries connected to a switch in an off state, the EMS compares the sum of the capacities of the powered batteries with the sum of the capacities of the non-powered batteries, and turns on the off switch of the non-powered batteries when the voltage of the battery with the smaller sum of the capacities is higher than the voltage of the battery with the larger sum of the capacities.

2. a plurality of main battery units each including a lithium ion battery and a switch for electrically connecting or disconnecting the lithium ion battery, and connected in parallel with each other; and a plurality of composite units each including an auxiliary battery unit each including a lead-acid battery, and connected in parallel with the plurality of main battery units, and connected in series with each other; an HV unit that directly or indirectly obtains measurements of voltage, current and temperature during charging and discharging of the lithium ion battery; an EMS that, when recognizing a lithium ion battery that has deteriorated due to repeated charging and discharging of the plurality of main battery units as a deteriorated battery, turns off a switch connected to the deteriorated battery and notifies an external device of information identifying the deteriorated battery; a housing that houses the plurality of composite units and the HV section, the plurality of main battery units are each configured with a basic connection number of main battery units set based on a specification for each of the plurality of composite units and a surplus connection number of main battery units set as a surplus to the basic connection number, For each of the multiple composite units, the number of basic connections is four or more, and the number of surplus connections is one or more; The EMS recognizes a lithium ion battery as a degraded battery when the measured value of at least one of the currents during charging and discharging deviates from a predetermined range, and if the EMS recognizes a lithium ion battery as a degraded battery among the measured values ​​obtained by simultaneously measuring the current of each lithium ion battery that constitutes each of the multiple main battery units during charging and discharging, the EMS excludes the measured value of the lithium ion battery that is recognized as a degraded battery among the multiple main battery units, and further calculates the average value of the remaining measured values, excluding the largest measured value and the smallest measured value from the remaining measured values.

3. The combined battery system of claim 2, wherein the EMS calculates the number of connections of the degraded batteries among the main battery sections for each of the composite units, and when the number of connections of the degraded batteries becomes equal to the number of surplus connections, sends a signal to the external device requesting replacement of the degraded batteries.

4. The auxiliary battery unit further includes an ammeter for measuring a current flowing through the lead-acid battery. an auxiliary switch that electrically connects or disconnects the lead-acid battery; An auxiliary BMS, The combined battery system according to any one of claims 1 to 3, wherein the auxiliary BMS turns on and off the auxiliary switch based on a measured value of a current flowing through the lead-acid battery, and notifies the external device of the measured value of the current flowing through the lead-acid battery via the HV unit and the EMS.

5. The combined battery system according to any one of claims 1 to 3, wherein the auxiliary battery unit further has a fuse that cuts off a current flowing to the lead-acid battery when an overcurrent flows to the lead-acid battery.

6. Each of the plurality of main battery units includes a BMS, The combined battery system according to any one of claims 1 to 3, wherein the BMS measures a voltage, a current, and a temperature of the lithium ion battery, calculates an SOC and an SOH based on the voltage, the current, and the temperature, and notifies the external device of the measured values ​​of the voltage, the current, and the temperature and the calculated values ​​of the SOC and SOH via the HV unit and the EMS.

7. 4. The combined battery system according to claim 1, wherein the HV unit measures a voltage, a current, and a temperature of the lithium ion battery, calculates an SOC and an SOH based on the voltage, the current, and the temperature, and notifies the external device of the measured values ​​of the voltage, the current, and the temperature and the calculated values ​​of the SOC and SOH via the EMS.

8. Further, a thermometer for measuring a temperature inside the housing; a heating and cooling device that changes the temperature inside the housing, The combined battery system according to any one of claims 1 to 3, wherein the EMS turns on and off at least one of the air conditioner and the switch based on the temperature of the lithium ion battery and the measurement value of the thermometer, and notifies the external device of the temperature of the lithium ion battery and the measurement value of the thermometer.

9. Further, a fire extinguisher that automatically detects and extinguishes a flame occurring inside the housing, The combined battery system according to any one of claims 1 to 3, wherein the EMS notifies the external device of the activation of the fire extinguisher when the fire extinguisher is activated.

10. Further, a hydrogen gas sensor for measuring a concentration of hydrogen gas inside the housing; A fan for ventilating air inside the housing, The auxiliary battery unit further includes an auxiliary switch that electrically connects or disconnects the lead-acid battery, 4. The combined battery system according to claim 1, wherein the EMS turns on and off at least one of the fan and the auxiliary switch based on the measured value of the hydrogen gas concentration, and notifies the external device of the measured value of the hydrogen gas concentration.

11. an organic gas sensor for measuring a concentration of an organic gas inside the housing; A fan for ventilating air inside the housing, The combined battery system according to any one of claims 1 to 3, wherein the EMS turns on and off at least one of the fan and the switch based on the measured value of the organic gas concentration, and notifies the external device of the measured value of the organic gas concentration.

12. The combined battery system according to any one of claims 1 to 3, further comprising a PCS arranged inside or outside the housing, which converts discharge power from the lithium ion battery and the lead storage battery to the external device from direct current to alternating current, and converts charging power from the external device to the lithium ion battery and the lead storage battery from alternating current to direct current.

13. The EMS turns on and off the switch based on the measured voltage value and notifies the external device of the measured voltage value; The combined battery system according to any one of claims 1 to 3, wherein the EMS receives notifications from the HV units housed in each of the plurality of housings.

14. The combined battery system according to any one of claims 1 to 3, wherein the predetermined range is 70 to 130% of both the average value of the measured value during charging and the average value of the measured value during discharging.

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