Power supply device and current control method therefor

Abstract

In the present invention, a control unit is configured to: estimate a first estimated current I1 flowing in a first battery block and a second estimated current I2 flowing in a second battery block by using, as input parameters, a first closed circuit voltage CCV1 of the first battery block, a first energizing current Ib1, a first combined resistance value R1 including an internal resistance value Ri1 of the first battery block, a second closed circuit voltage CCV2 of the second battery block, and the like; determine whether or not the estimated first estimated current I1 and the second estimated current I2 are each equal to or less than the maximum current value allowed at charging and discharging, in response to a request for at least one of state changes such as a state change involving electrical connection to or disconnection from a main conductive path MLN, in either one of the first battery block and the second battery block; and permit any one of the state changes when both of the estimated currents have been determined to be equal to or less than the maximum current value.

Description

Power supply device and current control method thereof

[0001] The present disclosure relates to a power supply device and a current control method thereof.

[0002] In order to drive electrical equipment using rechargeable secondary battery cells such as lithium-ion secondary batteries, power supply units and battery packs that house multiple secondary battery cells in a housing are used in various fields as power sources for mobile objects such as automobiles, construction machinery, and ships, or for power storage purposes (e.g., Patent Document 1).

[0003] In such power supply devices, a maximum value of the charge / discharge current (Operational Region: OR; hereafter referred to as "maximum current value") is specified to prevent deterioration of the lithium-ion secondary battery and ensure safe use. During charging and discharging, the current value flowing through the power supply device must be measured and controlled so as not to exceed this maximum current value.

[0004] Meanwhile, power supply devices are constructed by connecting multiple battery packs or battery modules (hereinafter collectively referred to as "battery blocks") in parallel depending on the output and capacity required for the power supply device. When multiple battery blocks are connected in parallel in this way, differences in the internal resistance, open circuit voltage, charge amount, etc. of each battery block can cause cross currents between the battery blocks or uneven charging and discharging currents, which can exceed the maximum current value.

[0005] Patent No. 7117534

[0006] One object of the present disclosure is to provide a power supply device and a current control method thereof in which a plurality of battery blocks are connected in parallel, and which suppresses cross currents and imbalances in charge / discharge currents so that the maximum current value is not exceeded.

[0007] A power supply device according to one embodiment of the present disclosure is a power supply device including: a main conductive path; a first battery block and a second battery block, each having a predetermined maximum current value allowed for charging or discharging, branched from the main conductive path and connected in parallel to each other; a first switch unit connected to the first battery block; a second switch unit connected to the second battery block; and a control unit that controls opening and closing of the first switch unit and the second switch unit, wherein the control unit estimates a first estimated current I1 flowing through the first battery block and a second estimated current I2 flowing through the second battery block using as input parameters a first combined resistance R1 including a first closed circuit voltage CCV1 of the first battery block, a first flow current Ib1, and an internal resistance Ri1 of the first battery block, and a second combined resistance R2 including a second closed circuit voltage CCV2 of the second battery block, a second flow current Ib2, and an internal resistance Ri2 of the second battery block; In response to a request for at least one of the following state changes, the battery control device determines whether the estimated first estimated current I1 and the estimated second estimated current I2 are equal to or less than the maximum current value allowed for charging and discharging, respectively; a state change of either the first battery block or the second battery block being electrically connected or disconnected to the main conductive path; a state change of either the first battery block or the second battery block starting or stopping charging and / or discharging by the first switch unit or the second switch unit; a state change of setting the total current flowing through the main conductive path when charging and / or discharging the first battery block and the second battery block; or a state change of connecting an additional third battery block in parallel with the first battery block and the second battery block while charging and / or discharging the first battery block and the second battery block, and if it is determined that both are equal to or less than the maximum current value, allows any of the state changes.

[0008] Furthermore, a power supply device according to another aspect of the present disclosure is a power supply device including: a main conductive path; a first battery block branched from the main conductive path and connected thereto, the first battery block having a predetermined maximum current value allowed for charging or discharging; a first switch unit connected in series with the first battery block; and a control unit that controls opening and closing of the first switch unit, wherein the first battery block is branched from the main conductive path and connectable to a second battery block in parallel with the first battery block; the second battery block is capable of controlling the opening and closing of a second switch unit connected in series with the second battery block by the control unit; and the control unit calculates a first estimated current I1 flowing through the first battery block and a second estimated current I2 flowing through the second battery block when the second battery block is connected to the first battery block as a first composite current including a first closed circuit voltage CCV1 of the first battery block, a first flow current Ib1, and an internal resistance Ri1 of the first battery block. The control circuit estimates a second combined resistance R2 including the resistance R1, the second closed circuit voltage CCV2 of the second battery block, the second current flowing current Ib2, and the internal resistance Ri2 of the second battery block as input parameters, and determines whether the estimated first estimated current I1 and the second estimated current I2 are equal to or less than a maximum current value allowed for charging and discharging in response to a request for at least one of a state change of electrical connection or disconnection of either the first battery block or the second battery block to the main conductive path, a state change of starting or stopping charging and / or discharging by the first switch unit or the second switch unit of either the first battery block or the second battery block, and a state change that sets a total current flowing through the main conductive path during charging and / or discharging of the first battery block and the second battery block, and if it determines that both are equal to or less than the maximum current value, allows one of the state changes.

[0009] Furthermore, a current control method for a power supply device according to another aspect of the present disclosure is a current control method for a power supply device including a main conductive path, a plurality of battery blocks branching from the main conductive path and connected in parallel to each other, each having a predetermined maximum current value allowed for charging or discharging, and a plurality of individual current detection units connected to each battery block for individually detecting signals related to the individual current flowing through each battery block, the method including the steps of: detecting signals related to the individual currents with each of the plurality of individual current detection units; estimating with a control unit an estimated individual current flowing through each of the plurality of battery blocks for a given total planned current flowing through the main conductive path based on the detected signals related to each individual current and the internal resistance values ​​of the plurality of battery blocks; and determining the total charging or discharging current flowing through the main conductive path so that none of the estimated individual currents exceeds the predetermined maximum current value in each battery block.

[0010] Still another aspect of the present disclosure provides a current control method for a power supply device including a main conductive path, a plurality of battery blocks branching from the main conductive path and connected in parallel, each having a predetermined maximum current value allowed for charging or discharging, and a plurality of individual current detection units connected to each battery block for individually detecting signals related to the individual current flowing through each battery block, the method including the steps of: detecting signals related to the individual currents with each of the plurality of individual current detection units; estimating with a control unit an estimated individual current flowing through each of the plurality of battery blocks for a given total planned current flowing through the main conductive path based on the detected signals related to each individual current and the internal resistance values ​​of the plurality of battery blocks; and determining the total charging or discharging current flowing through the main conductive path so that none of the estimated individual currents exceeds the predetermined maximum current value in each battery block.

[0011] Furthermore, a current control method for a power supply device according to another aspect of the present disclosure is a current control method for a power supply device including a main conductive path, a first battery block branched from the main conductive path and connected thereto, the first battery block having a predetermined maximum current value allowed for charging or discharging, and a control unit for controlling charging and discharging of the first battery block, wherein, during charging and / or discharging of the first battery block, at least one of a state change of branching off from the main conductive path and additionally connecting a second battery block in parallel with the first battery block, a state change of connecting or disconnecting either the first battery block and / or the second battery block, a state change of starting or stopping charging and / or discharging of the first battery block and / or the second battery block, and a state change of setting a total current flowing through the main conductive path during charging and / or discharging of the first battery block and / or the second battery block. and, when any of the state changes is detected, estimating a first estimated current I1 that is estimated to flow in the first battery block and a second estimated current I2 that is estimated to flow in the second battery block using as input parameters a first combined resistance R1 that includes a first closed circuit voltage CCV1, a first energization current Ib1, and an internal resistance Ri1 of the first battery block of the first battery block, and a second combined resistance R2 that includes a second closed circuit voltage CCV2, a second energization current Ib2, and an internal resistance Ri2 of the second battery block of the second battery block; determining whether the first estimated current I1 and the second estimated current I2 estimated by the control unit are each equal to or less than a maximum current value allowed; and, when it is determined that both the first estimated current I1 and the second estimated current I2 are equal to or less than the maximum current value, executing any of the state changes.

[0012] Furthermore, a current control method for a power supply device according to another aspect of the present disclosure is a current control method for a power supply device including a main conductive path, a first battery block and a second battery block branched from the main conductive path and connected in parallel to each other, each having a predetermined maximum current value allowed for charging or discharging, and a control unit that controls charging and discharging of the first battery block and the second battery block, the current control method including a control unit that controls charging and discharging of the first battery block and the second battery block, a state change of connection or disconnection of either the first battery block or the second battery block, a state change of starting or stopping charging and / or discharging of the first battery block and the second battery block, a state change that sets a total current flowing through the main conductive path when charging and / or discharging the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of starting or stopping charging and / or discharging of the first battery block and the second battery block, a state change of setting a total current flowing through the main conductive path when charging and / or discharging the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the first battery block and the second battery block, a state change of the second battery block and the first ... The method includes the steps of: detecting the occurrence of at least one of the state changes, during charging and / or discharging of two battery blocks, in which a third battery block is additionally connected in parallel with the first battery block and the second battery block; assuming, upon detecting any of the state changes, an assumed total current that is assumed to be passed through the main conductive path after any of the state changes; determining, based on the assumed assumed total current, whether a first assumed current that is assumed to flow through the first battery block and a second assumed current that is assumed to flow through the second battery block are each equal to or less than a maximum current value that is allowed; and executing any of the state changes when it is determined that both the first assumed current and the second assumed current are equal to or less than the maximum current value.

[0013] Any combination of the above components, and conversion of the expression of the present disclosure into an apparatus, system, method, computer program, etc., are also valid aspects of the present disclosure.

[0014] According to a power supply device and a current control method thereof according to one embodiment of the present disclosure, by estimating in advance the cross current between battery blocks connected in parallel, it is possible to set in advance so that the maximum current value allowed during charging and discharging is not exceeded, thereby preventing a situation in which the maximum current value is exceeded during charging and discharging, causing charging and discharging to be stopped.

[0015] FIG. 1 is a block diagram showing a power supply device according to a first embodiment. FIG. 2 is a block diagram showing the addition of a third battery block to FIG. 1. FIG. 3 is a block diagram showing the generation of a cross current. FIG. 4A is a circuit diagram showing a state in which a plurality of battery blocks are connected in parallel. FIG. 4B is an equivalent circuit diagram of each battery block. FIG. 5 is a block diagram showing a state change when a parallel-connected battery block is switched from disconnected to connected. FIG. 6A is a block diagram showing a battery block before charging. FIG. 6B is a block diagram showing a battery block for which charging is estimated. FIG. 6C is a block diagram showing a battery block for which the total planned current flow is estimated by increasing the total planned current flow from FIG. 6B. FIG. 6B is a block diagram showing a state in which an additional battery block is connected in parallel. FIG. 8A is a block diagram showing a discharging state. FIG. 8B is a block diagram showing a state in which the discharge current is reduced from FIG. 8A. FIG. 8C is a block diagram showing a state in which the discharge current is further reduced to zero from FIG. 8B. FIG. 8C is a block diagram showing a state in which the discharge current is further reduced to zero from FIG. 8B. FIG. 9 is a flowchart showing the procedure for checking whether a connection is possible when connected in parallel. FIG. 10 is a flowchart showing the procedure for adding a connection when charging during use. FIG. 11 is a flowchart showing the procedure for adding a connection when discharging during use. FIG. 12 is a flowchart showing the procedure for setting the charging current. FIG. 13 is a flowchart showing the procedure for setting the discharging current. FIG. 14 is a flowchart showing the procedure before discharging is stopped. FIG. 15 is a block diagram showing a power supply device according to a second embodiment.

[0016] The embodiments of the present disclosure may be specified by the following configurations and features.

[0017] In the power supply device according to another aspect of the present disclosure, in the above aspect, the control unit is configured to calculate the first estimated current I1 and the second estimated current I2 from the following equations.

[0018] I = (R × I all +CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2) I2=(R1×I all +CCV1-CCV2+Ib2×Ri2-Ib1×Ri1) / (R1+R2) (where I allis the total planned current flow; I1 is the estimated individual current flow of the first battery block; Ri1 is the internal resistance value of the first battery block; R1 is a first combined resistance value obtained by adding the internal resistance value Ri1 of the first battery block to the line resistance value Ro1 outside the first battery block; CCV1 is the closed circuit voltage of the first battery block; Ib1 is the individual current flow of the first battery block before the state change; I2 is the estimated individual current flow of the second battery block; Ri2 is the internal resistance value of the second battery block; R2 is a second combined resistance value obtained by adding the internal resistance value Ri2 of the second battery block to the line resistance value Ro2 outside the second battery block; CCV2 is the closed circuit voltage of the second battery block; Ib2 is the individual current flow of the second battery block before the state change. ) With the above configuration, by estimating the cross current between the parallel-connected battery blocks in advance, it is possible to set the current value in advance so that it does not exceed the maximum current value allowed for charging and discharging, thereby avoiding a situation in which the maximum current value is exceeded, including the cross current that is stopped during charging and discharging, causing charging and discharging to be stopped.

[0019] A power supply device according to another aspect of the present disclosure includes a main conductive path, a plurality of battery blocks branching from the main conductive path and connected in parallel to each other, each having a predetermined maximum current value allowed for charging or discharging, a plurality of individual current detection units connected to each battery block and individually detecting a signal related to the individual current flowing through each battery block, a total current detection unit detecting a signal related to the total current flowing through the main conductive path, and a control unit that estimates an estimated individual current flowing through each of the plurality of battery blocks for a given total planned current flowing through the main conductive path based on the signals related to the individual currents detected by the plurality of individual current detection units, the internal resistance values ​​of the plurality of battery blocks, and the signal related to the total current flowing through the main conductive path, and determines the total charging or discharging current flowing through the main conductive path so that none of the estimated individual currents exceeds the predetermined maximum current value allowed for charging or discharging of each battery block. With the above configuration, by estimating the cross current between battery blocks connected in parallel in advance, it is possible to set the current value in advance so that it does not exceed the maximum current value allowed for charging and discharging, thereby preventing the current from exceeding the maximum value during charging and discharging, which would cause charging and discharging to be stopped.

[0020] Furthermore, a power supply device according to another aspect of the present disclosure includes a main conductive path, n battery blocks branched from the main conductive path and connected in parallel, n (n≧2) individual current detection units connected to each battery block and configured to individually detect a signal related to the individual current flowing through each battery block, n individual closed-circuit voltage detection units connected to each battery block and configured to individually detect a signal related to the individual closed-circuit voltage of each battery block, a total current detection unit for detecting a signal related to the total current flowing through the main conductive path, and a control unit that estimates an estimated individual current flowing through each of the n battery blocks based on at least one of the signals related to the individual closed-circuit voltages detected by the n individual closed-circuit voltage detection units, the internal resistance values ​​of the n battery blocks, and the signal related to the total current flowing through the main conductive path, and determines the total charging or discharging current flowing through the main conductive path so that none of the estimated individual currents exceeds a maximum current value allowed for charging or discharging each battery block. With the above configuration, by estimating the cross current between battery blocks connected in parallel in advance, it is possible to set the current value in advance so that it does not exceed the maximum current value allowed for charging and discharging, thereby preventing the current from exceeding the maximum value during charging and discharging, which would cause charging and discharging to be stopped.

[0021] Furthermore, in a power supply device according to another aspect of the present disclosure, in any of the above aspects, the control unit is configured to control, when determining the total charging or discharging current flowing through the main conductive path, such that none of the estimated individual currents exceed the maximum current value allowed for charging or discharging of each battery block, by calculating the output voltages of the battery blocks, which reflect the path resistance values ​​of the battery blocks connected in parallel, to be equal.

[0022] Furthermore, in the power supply device according to another aspect of the present disclosure, in any of the above aspects, the control unit is configured to calculate the estimated individual energization current based on the following simultaneous linear equations with 3n unknowns (n≧1): OCV1=CCV1−Ib1×Ri1 OCV2=CCV2−Ib2×Ri2 ... OCV n =CCVn -Ib n ×Ri n VPACK1=OCV1+I1×R1 VPACK2=OCV2+I2×R2... VPACK n =OCV n +I n ×R n I all =I1+I2+...+I n VPACK1=VPACK2=. .. .. =VPACK n (In the above formula, CCV n is the closed circuit voltage of the nth battery block; Ib n is the current flowing through the nth battery block; Ri n is the internal resistance value of the nth battery block; I n is the estimated individual current flowing through the nth battery block; VPACK n is the output voltage of the nth battery block before the state change. n is the internal resistance value Ri of the nth battery block n The resistance value Ro of the line outside the nth battery block n The nth combined resistance value obtained by adding all is the total planned current to be passed;) Furthermore, the power supply device according to another aspect of the present disclosure, in any of the above aspects, further includes a plurality of individual switch units connected to each battery block, respectively, and capable of individually switching the parallel connection ON / OFF.

[0023] Furthermore, the power supply device according to another aspect of the present disclosure is any one of the above aspects, further including an overall switch section provided on the main conduction path.

[0024] Furthermore, in another aspect of the power supply device of the present disclosure, in any of the above aspects, the power supply device further includes a charge / discharge element for controlling the total charging or discharging current flowing through the main conductive path in accordance with the estimated individual currents estimated by the control unit.

[0025] Furthermore, a current control method for a power supply device according to another aspect of the present disclosure is a current control method for a power supply device including a main conductive path, a first battery block and a second battery block branched from the main conductive path and connected in parallel to each other, each having a predetermined maximum current value allowed for charging or discharging, and a control unit that controls charging and discharging of the first battery block and the second battery block, the current control method including a state change of connection or disconnection of either the first battery block or the second battery block, a state change of starting or stopping charging and / or discharging of the first battery block and the second battery block, a state change of setting a total current flowing through the main conductive path when charging and / or discharging the first battery block and the second battery block, a state change of the charging and / or discharging of ... and / or a state change in which a third battery block is additionally connected in parallel with the first battery block and the second battery block during discharging; and when any of the state changes is detected, estimating a first estimated current I1 that is estimated to flow in the first battery block and a second estimated current I2 that is estimated to flow in the second battery block after any of the state changes, using as input parameters a first closed circuit voltage CCV1 of the first battery block, a first flow current Ib1, a first combined resistance R1 that includes an internal resistance Ri1 and a path resistance of the first battery block, and a second closed circuit voltage CCV2 of the second battery block, a second flow current Ib2, and a second combined resistance R2 that includes an internal resistance Ri2 and a path resistance of the second battery block.

[0026] Furthermore, a current control method for a power supply device according to another aspect of the present disclosure, in any of the above aspects, further includes the steps of: determining whether the first estimated current I1 and the second estimated current I2 estimated by the control unit are each equal to or less than an allowable maximum current value; and, when it is determined that both the first estimated current I1 and the second estimated current I2 are equal to or less than the maximum current value, executing one of the state changes.

[0027] Furthermore, in a current control method for a power supply device according to another aspect of the present disclosure, in any of the above aspects, the maximum current value includes a first maximum charging current value allowed in charging the first battery block, a first maximum discharging current value allowed in discharging, a second maximum charging current value allowed in charging the second battery block, and a second maximum discharging current value allowed in discharging.

[0028] Furthermore, in a current control method for a power supply device according to another aspect of the present disclosure, in any of the above aspects, the control unit controls charging and discharging of the first battery block and the second battery block by turning on and off a first switch unit connected to the first battery block and a second switch unit connected to the second battery block.

[0029] In still another aspect of the present disclosure, in the current control method for a power supply device, in any of the above aspects, if it is determined that either the first assumed current or the second assumed current is greater than the maximum current value in the step of determining whether the first assumed current and the second assumed current are less than the maximum current value, the step of assuming an assumed total conduction current reduces the total conduction current, and determines whether the first assumed current and the second assumed current are less than the maximum current value based on the assumed assumed total conduction current, and repeats the above steps until it is determined that both the first assumed current and the second assumed current are less than the maximum current value. As a result, safe charging and discharging can be achieved by reducing the total conduction current until both the first assumed current and the second assumed current are less than the maximum current value.

[0030] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, such that multiple elements are shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0031] The power supply device of the present disclosure can be used as a driving power source for construction machinery, ships, forklifts, etc., a stationary power supply, for example, a backup power supply for servers, a power storage device for storing power obtained from solar power generation or the like for home, office, or factory use, or a power supply for daytime peak cutting, etc. Below, a power supply device for construction machinery will be described as one embodiment of the present disclosure.

[0032] [Embodiment 1] Fig. 1 shows a power supply device 100 according to embodiment 1 of the present disclosure. The power supply device 100 shown in this figure includes a main conduction path MLN, an overall current detection unit 6, an overall switch unit 7, a plurality of battery blocks 1, a plurality of individual switch units 3, a plurality of individual current detection units 2, and a control unit 5. This power supply device 100 is used in connection with an electric device LOD to be driven and a charger CHG. The charger CHG includes a charge / discharge element FT for controlling the overall current flowing through the main conduction path MLN of the power supply device 100 for charging or discharging.

[0033] (Main Conduction Path MLN) The main conduction path MLN is a path that carries a charging current when charging the power supply device 100 and a discharging current when discharging (both of which are collectively referred to as "charging and discharging currents"). An external connection terminal OUT and a signal terminal SIG are provided on the edge of the main conduction path MLN for connecting an electric device LOD to be driven and a charger CHG that are external to the power supply device 100. In addition, an overall current detection unit 6 and an overall switch unit 7 are arranged on the main conduction path MLN.

[0034] (Total Current Detector 6) The total current detector 6 is a component for detecting a signal related to the total current flowing through the main conduction path MLN. Typically, the total current detector 6 is configured with a current detection resistor. The voltage across the current detection resistor is detected as the signal related to the total current, and the control unit 5 calculates the total current.

[0035] (Overall Switch Unit 7) The overall switch unit 7 is provided on the main conduction path MLN. The overall switch unit 7 cuts off the overall current that is supplied to the main conduction path MLN and branched off to each battery block 1. The control unit 5 controls the ON / OFF of the overall switch unit 7.

[0036] The control unit 5 is configured, for example, by a microcomputer mainly composed of a CPU (Central Processing Unit) and a memory. In other words, the control unit 5 is realized by a computer having a CPU and a memory, and the computer functions as the control unit 5 when the CPU executes a program stored in the memory. Here, the program is pre-recorded in the memory of the control unit 5, but it may also be provided via a telecommunications line such as the Internet or recorded on a (non-transitory) recording medium such as a memory card.

[0037] (Battery Block 1) Multiple battery blocks 1 are connected on the main conduction path MLN. Each battery block 1 branches off from the main conduction path MLN and is connected in parallel with one another. As a result, the total current flowing through the main conduction path MLN during charging and discharging of the power supply device 100 branches off and is passed through each battery block 1. Each battery block 1 is configured by connecting multiple secondary battery cells 11 in series or parallel. In the example of FIG. 1 , the multiple battery blocks 1 include a first battery block 10 and a second battery block 20. The number of battery blocks 1 can be three or more.

[0038] It is also possible to add another battery block 1. For example, as shown in FIG. 2, it is also possible to add a third battery block 30 in parallel with the first battery block 10 and the second battery block 20.

[0039] Each battery block 1 is configured by connecting multiple secondary battery cells 11 in series or parallel. The secondary battery cells 11 may have a cylindrical, rectangular, or pouch-shaped outer can, as appropriate. Lithium-ion secondary batteries are suitable for use as the secondary battery cells 11. However, lithium polymer batteries and nickel-metal hydride batteries can also be used as secondary battery cells instead of lithium-ion batteries. Therefore, the present disclosure does not limit the secondary battery cells to lithium-ion batteries, and any rechargeable battery can be used as the secondary battery cells.

[0040] (Maximum Current Value) From the viewpoint of safety, each battery block 1 has a predetermined maximum current value (Operational Region: OR) that is allowed for charging or discharging. The maximum current value is set depending on the total number of secondary battery cells 11 constituting the battery block 1, the number of series / parallel connections, the capacity and rated current of each secondary battery cell 11, the application and environment in which the power supply device 100 is used, the required safety, and other factors. Specifically, the first battery block 10 has a maximum first current value. The second battery block 20 has a maximum second current value. These maximum first current value and maximum second current value may be the same or different. The maximum first current value includes a maximum first charging current value allowed for charging the first battery block 10 and a maximum first discharging current value allowed for discharging. The maximum second current value includes a maximum second charging current value allowed for charging the second battery block 20 and a maximum second discharging current value allowed for discharging.

[0041] (Individual switch unit 3) The individual switch unit 3 is connected to each battery block 1. Each individual switch unit 3 can individually switch ON / OFF each of the parallel-connected battery blocks 1. In the example of FIG. 1 , the individual switch unit 3 includes a first switch unit 13 connected in series with the first battery block 10 and a second switch unit 23 connected in series with the second battery block 20. The opening and closing of these first switch unit 13 and second switch unit 23 is controlled by the control unit 5.

[0042] (Individual Current Detection Unit 2) Multiple individual current detection units 2 are connected to multiple battery blocks 1. Each battery block 1 is connected to each individual battery block 1 and individually detects a signal related to the individual current flowing through each battery block 1. For example, the individual current detection unit 2 is configured with a current detection resistor. In this case, the voltage across the current detection resistor is detected as a signal related to the individual current flowing through each battery block 1, and the control unit 5 calculates the individual current flowing through each battery block 1 from the resistance value of the current detection resistor. In this disclosure, this configuration of calculating the individual current flowing through each battery block 1 from the voltage of the resistance value is referred to as "individually detecting the individual current flowing through each battery block 1." In the example of FIG. 1 , the individual current detection unit 2 includes a first current detection unit 12 connected in series with the first battery block 10 and a second current detection unit 22 connected in series with the second battery block 20.

[0043] (Individual Closed Circuit Voltage Detector 4) The power supply device 100 may also include multiple individual closed circuit voltage detectors 4 that detect the closed circuit voltage of each battery block 1. The multiple individual closed circuit voltage detectors 4 are connected to the respective battery blocks 1 and individually detect signals related to the individual closed circuit voltage of each battery block 1. In the example of FIG. 1 , the control unit 5 detects the closed circuit voltage of each battery block 1. Specifically, the control unit 5 includes a first closed circuit voltage detector 14 that detects the first closed circuit voltage of the first battery block 10 and a second closed circuit voltage detector 24 that detects the second closed circuit voltage of the second battery block 20. In the example of FIG. 2 , the control unit 5 further includes a third closed circuit voltage detector 34 that detects the third closed circuit voltage of the third battery block 30.

[0044] (Control Unit 5) The control unit 5 controls the ON / OFF of each individual switch unit 3 and the overall switch unit 7. The control unit 5 also communicates with the electric devices LOD to be driven and the charger CHG connected to the power supply device 100, and outputs the value of the overall current flow as the charge / discharge current. The charger CHG and the electric devices LOD charge or discharge in accordance with the requested value of the overall current flow transmitted from the control unit 5. Such a control unit 5 can be implemented by a CPU, an ASIC, a microcomputer, or the like.

[0045] (Individual Current Estimation Function) The control unit 5 also has an individual current estimation function that estimates the estimated individual currents that will be passed through each of the multiple battery blocks 1. The individual current estimation function estimates the estimated individual currents based on various parameters from the total planned current that will be passed through the main conduction path MLN. Examples of the parameters include signals related to the individual currents detected by the multiple individual current detection units 2, the combined resistance values ​​of the multiple battery blocks 1, and a signal related to the total current detected by the total current detection unit 6.

[0046] (Total Current Determination Function) The control unit 5 also has a total current determination function that determines whether to pass a given total planned current through the main conduction path MLN as is, or whether to change the total planned current and pass it. The total current determination function determines the total charging or discharging current to be passed through the main conduction path MLN so that none of the estimated individual currents exceeds the maximum current value allowed for charging or discharging of each battery block 1. Here, changing the total planned current includes not only decreasing the total planned current but also increasing it.

[0047] (State Changes) The estimation of individual current flows and the determination of the total current flow by the control unit 5 are performed at the timing of specific state changes that may cause cross currents. State changes include: starting charging or discharging a battery block 1; stopping charging or discharging a battery block 1; changing the total current flow while charging or discharging a battery block 1; connecting an additional battery block 1 while charging or discharging a battery block 1; connecting an additional battery block 1 while charging or discharging a battery block 1 is stopped; connecting or disconnecting any of the battery blocks 1.

[0048] This configuration makes it possible to estimate in advance the cross current between the parallel-connected battery blocks 1 and set it so that it does not exceed the maximum current value allowed during charging and discharging, thereby preventing the current from exceeding the maximum value during charging and discharging and causing the charging and discharging to be stopped.

[0049] When multiple battery blocks 1 are connected in parallel, the overall current branches off from the main conduction path MLN, and individual currents flow through each battery block 1. In theory, if the characteristics of each battery block are the same, the individual currents should be equal. However, in reality, imbalances occur due to variations in the characteristics of the secondary battery cells 11 that make up the battery block 1, ambient temperature, and combined resistance, resulting in unequal individual currents, as shown in Figure 3 . This results in biased or cross currents in the charging and discharging currents between the parallel-connected battery blocks 1 (collectively referred to as "cross currents" in this disclosure). If the individual current Ii concentrates in a specific battery block, it may exceed the maximum allowable current value OR(Iimax), triggering a safety function to stop charging and discharging. Cross currents are particularly likely to occur when starting or stopping charging and discharging, or when adding a new battery block.

[0050] To avoid this situation, the power supply device 100 according to this embodiment estimates the cross current in advance from the immediately preceding current flow, and adjusts the total current flow so that it does not exceed the maximum allowable current value, thereby preventing the charging / discharging from being stopped. As a result, charging can be completed in a short time even if there is an imbalance between the battery blocks.

[0051] Here, a procedure for estimating cross currents and determining the total current flowing through the n battery blocks 1 in accordance with the parameters of the equivalent circuit shown in Fig. 4B when n battery blocks 1 are connected in parallel as shown in Fig. 4A will be described. Each of the n battery blocks 1 is connected to an individual current detector 2 and an individual closed-circuit voltage detector 4. That is, the power supply device 100 includes the n battery blocks 1, the n individual current detectors 2, and the n individual closed-circuit voltage detectors 4, in addition to the control unit 5 and the total current detector 6. The control unit 5 estimates the estimated individual current flowing through the n battery blocks 1 based on at least one of signals related to the individual closed-circuit voltages detected by the n individual closed-circuit voltage detectors 4, the combined resistance values ​​of the n battery blocks 1, and a signal related to the total current flowing through the n battery blocks 1, and determines the total planned current flowing through the main conduction path MLN for charging or discharging I so that none of the estimated individual current flowing through the n battery blocks 1 exceeds the maximum current value allowed for charging or discharging. all Specifically, the estimated individual energization current I is determined by the following equation: n However, the estimated individual current I must not exceed the maximum current value. n If exceeds the maximum current value, the total current I all is reduced, and the estimated individual energization current I n The process of calculating the estimated individual energization current I is repeated. n When the maximum current value is no longer exceeded, the total current I all is determined as the total current flow, where: Closed circuit voltage of the nth battery block: CCV n Internal resistance value of the nth battery block: Ri n Internal resistance value Ri of the nth battery block n and the path resistance value Ro of the nth battery block: R n The path resistance value Ro outside the battery block is the internal resistance value Ri n Since it is extremely small compared to the total current, it is ignored here. all Individual current flowing through the nth battery block before the state change: Ib n Estimated individual current flowing through the nth battery block when the state changes: I nOutput voltage of the nth battery block before the state change: VPACK n Then, the estimated individual energization current is calculated based on the following simultaneous linear equations with 3n unknowns (n≧1).

[0052] [Equation 1] OCV1 = CCV1 - Ib1 x Ri1 OCV2 = CCV2 - Ib2 x Ri2 ... OCV n =CCV n -Ib n ×Ri n VPACK1=OCV1+I1×R1 VPACK2=OCV2+I2×R2... VPACK n =OCV n +I n ×R n I all =I1+I2+...+I n VPACK1=VPACK2=. .. .. =VPACK n Here, as an example, for n = 2, i.e., the case shown in Figure 1 , the estimated individual current flow after a state change is calculated. State changes include: A state change in connection or disconnection of either the first battery block 10 or the second battery block 20; a state change in the start of charging and / or discharging of the first battery block 10 or the second battery block 20; a state change in the stop of charging and / or discharging of the first battery block 10 or the second battery block 20; a state change in setting the total current flow during charging and / or discharging of the first battery block 10 or the second battery block 20; and a state change in the connection of an additional third battery block 30 in parallel with the first battery block 10 or the second battery block 20 during charging and / or discharging of the first battery block 10 or the second battery block 20. "Before the state change" refers to the time immediately before the state change, i.e., immediately before the estimation is performed. The state change in connection or disconnection of the battery block 1 can preferably be achieved by turning the individual switch unit 3 ON / OFF. For example, the first battery block 10 is changed to a connected or disconnected state by the first switch unit 13. Similarly, the state of the second battery block 20 is changed between a connected state and a disconnected state by the second switch unit 23 .

[0053] First, the open circuit voltage (OCV) n the block applied current Ib before the state change n , closed circuit voltage CCVn , internal resistance Ri n The open circuit voltages OCV1 and OCV2 are calculated using the following formula:

[0054] [Equation 2] OCV1=CCV1-Ib1×Ri1 [Equation 3] OCV2=CCV2-Ib2×Ri2 Furthermore, the output voltage VPACK of the battery block 1 before the state change n is the estimated block current I n Using this, it is expressed as follows:

[0055] [Equation 4] VPACK1=OCV1+I1×R1 [Equation 5] VPACK2=OCV2+I2×R2 Here, since the first battery block 10 and the second battery block 20 are connected in parallel, the following equations hold.

[0056] [Equation 6] VPACK1 = VPACK2 From the above, the estimated individual energization current I n is expressed by the following equation:

[0057] [Equation 7] I = (R × I all +CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2) [Equation 8] I2=(R1×I all+CCV1-CCV2+Ib2×Ri2-Ib1×Ri1) / (R1+R2) (State change of battery block 1) The timing for executing this individual energization current estimation function is the timing when some state change occurs in battery block 1. Therefore, the control unit 5 executes the individual energization current estimation function when it detects a state change in battery block 1. For example, when a signal to start or end charging or discharging is input to the power supply device 100 from an external device such as a charger CHG or electrical device LOD, i.e., when a state change command is received, the control unit 5 executes the individual energization current estimation function before executing the state change. Then, it determines whether each calculated estimated individual energization current is equal to or less than the maximum current value. If all estimated individual energization currents are equal to or less than the maximum current value, the state change command is executed. For example, the control unit 5 starts or ends charging or discharging. On the other hand, if any estimated individual current flows exceed the maximum current value, the given total planned current is reduced, and the individual current flow estimation function is executed again, repeating the process until all estimated individual current flows are equal to or less than the maximum current value. In this way, safe charging and discharging can be achieved by taking cross current into consideration, even between battery blocks with mismatched cell balance. Note that the cross current flowing between multiple battery blocks connected in parallel is based on the output voltage VPACK of each battery block, which reflects the path resistance value of each battery block, and the output voltages VPACK of multiple battery blocks connected in parallel are equal when charging and discharging.

[0058] Battery block status changes include software-related changes that are executed when information is transmitted from the outside to the power supply unit, such as the start and end of charging or discharging, as well as hardware-related changes such as the physical addition or removal of battery blocks. In these cases, the power supply unit is not notified of the status change information in advance, and the change occurs at a timing that the power supply unit cannot anticipate, so the power supply unit must be able to recognize such hardware status changes and respond autonomously.

[0059] For example, a state change detection unit that detects state changes can be provided in the power supply device to monitor the occurrence of state changes. Such a state change detection unit can be, for example, a microswitch or photoelectric sensor that detects the addition or removal of a battery block. When the detection unit detects a state change, the control unit 5 quickly grasps the change and executes an individual current estimation function and a total current determination function. It can support the execution of the state change by prompting an external device to change the total current, or, if necessary, shut off the total switch unit 7 to prevent the execution of the state change. Note that a battery block is connected with the individual switch unit of the battery block to be added turned OFF. The current is estimated at the time of connection to determine whether to turn ON the individual switch. Meanwhile, the battery voltage (closed circuit voltage CCV) can be transmitted to the control unit via communication or other means when the battery block is connected, even if the individual switch is OFF.

[0060] Alternatively, the power supply device may be configured to execute the individual current flow estimation function or the total current flow determination function unconditionally, without having a physical state change detection unit, by detecting a large current change using an overall current detection unit or a large voltage change using a voltage detection unit, thereby determining that a state change has occurred.

[0061] For example, as shown in Figure 2, when the power supply device 100 detects by some means a state change in which a third battery block 30 is physically added, it executes the individual current flow estimation function and the total current flow determination function, and updates the total current flow if necessary. Note that when determining whether or not a parallel connection is possible when charging and discharging are stopped, among state changes, the total planned current flow is zero, so there is no need to execute the total current flow determination function.

[0062] (1: Checking Connection Possibility in Parallel Connection) Considering a configuration in which one parallel first battery block 10 is used as the reference, as shown in FIG. 15 , and a second battery block 20, etc. are attached or detached in this state, since each battery block is not necessarily used simultaneously or for the same length of time, cross currents may occur between parallel-connected battery blocks due to battery block degradation, such as capacity or internal resistance. As a result, cross currents may occur between parallel-connected battery blocks, potentially exceeding the maximum current value. Similarly, in an environment in which multiple battery blocks are connected, cross currents may occur due to cell imbalance or other factors. Specific examples of state changes are described below. First, checks for connection possibility in parallel connection are described. Here, we consider a state change in which the third battery block 30 is switched from a disconnected state to a connected state in a power supply device 100 in which, as shown in FIG. 5 , the battery blocks 1 are previously connected in parallel and can be switched between connected and disconnected using individual switch units 3. In this case, cross currents are expected to occur when the third battery block 30 is connected in parallel in addition to the first battery block 10 and second battery block 20, as shown in FIG. 1 . To prevent this cross current from exceeding the maximum current value of each battery block, the individual assumed currents are calculated and a determination is made as to whether the first assumed current assumed to flow through the first battery block, the second assumed current assumed to flow through the second battery block, and the third assumed current assumed to flow through the third battery block are each below their respective maximum allowable current values. In this case, the state change is executed if it is determined that all of these currents are below their respective maximum current values. For example, consider the case shown in FIG. 15 where a second battery block 20 is added while charging or discharging of the first battery block 10 is stopped, specifically, when the second switch unit 23 is switched from OFF to ON. In this case, a second current flows through the second battery block 20. The second estimated current I2 is calculated so that the second current does not exceed its maximum value. As an example, Table 1 shows the parameters of the second battery block 20 when the second switch unit 23 is in the OFF state, and Table 2 shows the results of the individual current flow estimation function's calculation of the second estimated current I2 when the second switch unit 23 is in the ON state.

[0063]

[0064]

[0065] If the maximum current value of the third battery block 30 is 10 A, then according to Table 2, the third estimated current I3 exceeds the maximum current value, and therefore this state change is not permitted.

[0066] On the other hand, if the third estimated current I3 when the battery is in the ON state is calculated as shown in Table 3 below, the third estimated current I3 is smaller than the maximum current value, and the state change is permitted. In this way, by evaluating whether or not to allow the state change of connecting the third battery block 30 in parallel before the state change is executed, a safe state change can be achieved.

[0067]

[0068] (2: Setting the charging and discharging current) Next, as another specific example of a state change, setting the charging and discharging current will be described. Here, we consider an example of setting the charging and discharging current for a power supply device in which a second battery block 20 is connected in parallel to a first battery block 10 as shown in FIG. 15. To avoid deviation from the maximum current value while taking into account the occurrence of cross current, the individual assumed currents are calculated, and then the total planned current is determined. Here, a margin is taken into account for the maximum charging and discharging current of each battery block, and the total planned current is calculated so that it becomes (maximum charging and discharging current - margin). The margin value can be set uniformly or individually. Specifically, assuming that charging is + and discharging is -, [Equation 9] |I1 = (R2 × I all + (CCV2-Ib2×Ri2)-OCV1) / (R1+R2) |> Charging OR-Margin | I2=(R1×I all +OCV1-(CCV2-Ib2×Ri2) / (R1+R2)|>Charge OR-Margin. Note that although the example shown here is of two battery blocks connected in parallel, if n battery blocks are connected in parallel, the calculation can be based on simultaneous linear equations with n unknowns (n≧1).

[0069] (2-1: In the case of charging) Substitute "maximum charging current - margin" into the formula for I1, and I all , I2, I3...I nCalculate the value and substitute "maximum charging current - margin" into the formula for I2, and get I all , I1, I3, I4...I n Calculate...I n Substitute "maximum charging current - margin" into the formula and get I all , I1, I2, I3...I n-1 Calculate I all >0 and I1, I2...I n The maximum value of "maximum charging current - margin" is calculated as positive. all Determine.

[0070] (2-2: In the case of discharge) Substitute "- (maximum discharge current - margin)" into the formula for I1, and all , I2, I3...I n Calculate the value and substitute "- (maximum discharge current - margin)" into the formula for I2. all , I1, I3, I4...I n Calculate...I n Substitute "- (maximum discharge current - margin)" into the formula and get I all , I1, I2, I3...I n-1 Calculate I all <0 and I1, I2...I n The calculation where the minimum value of is "- (maximum discharge current - margin)" is taken as positive. all Determine.

[0071] Consider a state change in which the charging currents of the parallel-connected first battery block 10, second battery block 20, and third battery block 30 are set as shown in FIG. 6A . The maximum current value is 10 A for each battery block 1. For example, when a total current of 10 A is applied, a first current Ib1 of 2 A is applied to the first battery block 10, a second current Ib2 of 7 A is applied to the second battery block 20, and a third current Ib3 of 1 A is applied to the third battery block 30, as shown in FIG. 6A . In this state, the estimated individual currents are calculated as shown in FIG. 6B : the first current Ib1 is 4 A, the second current Ib2 is 5 A, and the third current Ib3 is 1 A. All of the estimated individual currents are greater than the maximum current value, and in this case, are less than 50% of the maximum current value. In this case, the total energization current can be increased, and by supplying a larger charge / discharge current to each battery block 1 within a range below the maximum current value, charging / discharging can be completed in a shorter time. Therefore, the total energization current determination function is executed to increase the total planned energization current. As a result, for example, in the case of charging, as shown in FIG. 6C , the first energization current Ib1 is calculated to be 6 A, the second energization current Ib2 is calculated to be 7 A, and the third energization current Ib3 is calculated to be 2 A. By requesting the external charger CHG to increase the total energization current accordingly, charging can be completed in a shorter time. Similarly, in the case of discharging, the first energization current Ib1, the second energization current Ib2, and the third energization current Ib3 are calculated, and the total energization current can be increased to perform discharging.

[0072] In this way, even in the case of a state change such as setting the charging current, the total planned current to be supplied is estimated and requested to the charger CHG while avoiding deviation from the maximum current value due to imbalance in the charging current, thereby enabling efficient charging. Similarly, in the case of setting the discharging current, the total planned current to be supplied is estimated and the maximum possible discharge current is notified to the electric device LOD while avoiding deviation from the maximum current value due to imbalance in the discharging current, thereby enabling efficient discharging.

[0073] Of course, if the charge / discharge current is large and exceeds the maximum current value, this is reduced to achieve safe and rapid charge / discharge control. For example, consider a case where the parameters before setting the charge current are as shown in Table 4, and the result of calculating the estimated individual current flowing after the change using the individual current flowing current estimation function is as shown in Table 5.

[0074]

[0075]

[0076] If the maximum charging current value for each battery block 1 were set to 20 A, this state change would not be permitted because the estimated individual energization current would exceed the maximum current value, as shown in Table 5. Therefore, the total planned energization current was reduced from 40 A to 30 A, and the estimated individual energization current was estimated again, as shown in Table 6.

[0077]

[0078] As shown in Table 6, the estimated individual energization current can be suppressed to be smaller than the maximum current value, so the state change is permitted with the updated parameters, that is, with the total planned energization current set to 30A.

[0079] (3: Confirmation of Possibility of Additional Connections During Use) Another state change, namely, confirmation of possibility of additional connections during use, will now be described. For example, consider whether a state change, such as adding a new battery block to a battery block 1, can be confirmed as shown in FIG. 7 for the purpose of increasing the total capacity of a power supply device. Here, a new second battery block 20 is connected in parallel to a first battery block 10. For the sake of explanation, this figure shows the physical addition of the second battery block 20. However, as with FIG. 5 described above, the second battery block 20 may be added by connecting the second battery block 20 in parallel and then turning on the second switch unit 23 connected in series to the second battery block 20. Here, too, when adding a second battery block 20, the charging current flowing through each battery block 1 is estimated, and if it is confirmed that the current does not exceed the respective maximum current values, the additional connection during charging is permitted. Similarly, when discharging, the discharging current flowing through each battery block 1 is estimated, and if it is confirmed that the current does not exceed the respective maximum current values, the additional connection during discharging is permitted.

[0080] For example, consider a case where the parameters before the additional connection are in the state shown in Table 7, and the estimated individual energization current after the additional connection is calculated using the individual energization current estimation function and is in the state shown in Table 8.

[0081]

[0082]

[0083] If the maximum current value for charging each battery block 1 is set to 20 A, then according to Table 8, the estimated individual energization current exceeds the maximum current value, and therefore this state change is not permitted.

[0084] On the other hand, if the estimated individual current flowing when the third battery block 30 is additionally connected is calculated as shown in Table 9 below, the estimated individual current flowing is smaller than the maximum current value, and the state change is permitted. In this way, by evaluating whether or not the state change of additionally connecting the third battery block 30 is possible before the state change is executed, a safe state change can be achieved.

[0085]

[0086] (4: Stop of charging / discharging) Finally, as another state change, the stop of charging / discharging will be described. In the case of stopping during discharging, "maximum charging current - margin" is substituted into the formula for I1 in the above-mentioned equation (9), and I all , I2, I3...I n Calculate the value and substitute "maximum charging current - margin" into the formula for I2, and get I all , I1, I3, I4...I n Calculate...I n Substitute "maximum charging current - margin" into the formula and get I all , I1, I2, I3...I n-1 Calculate I all ≧0 and I1, I2...I n The maximum value of "maximum charging current - margin" is calculated as positive. all Although the case where two battery blocks are connected in parallel is described here, when n battery blocks are connected in parallel, calculations can be performed based on simultaneous linear equations with n unknowns (n≧1) in the same manner as above.

[0087] Next, the case of stopping discharging during discharge will be described with reference to Figures 8A to 8C. In the example shown in Figure 8A, discharging is performed with the total planned current set to 50 A. If the discharge current were suddenly reduced to 0 A in this state, cross currents would occur between the parallel-connected battery blocks, potentially exceeding the maximum current value. Therefore, the estimated individual currents are estimated while taking the cross currents into account, and a warning is issued if the maximum current value is exceeded. As shown in Figure 8B, the estimated individual currents and the total planned current are updated while gradually decreasing the total planned current. Finally, as shown in Figure 8C, the total planned current is set to 0 A and discharging is stopped. This reduces the burden on the battery block 1 and safely stops discharging.

[0088] For example, let us assume that the parameters before the discharge is stopped are in the state shown in Table 10, and that the estimated individual currents after the discharge is stopped, i.e., when the discharge current is immediately changed from 80 A to 0 A, are calculated by the individual current current estimation function to be in the state shown in Table 11.

[0089]

[0090]

[0091] If the maximum discharge current value of each battery block 1 is 20 A, then according to Table 11, the estimated individual current flow is 40 A, which exceeds the maximum current value, and therefore this state change is not permitted. In other words, the discharge current is not changed from 80 A to 0 A.

[0092] Alternatively, if the estimated individual current flowing when the discharge current is reduced from 80 A to 30 A is calculated as shown in Table 12 below, the estimated individual current flowing is smaller than the maximum current value, and the state change is permitted. In this way, the discharge is stopped while reducing the discharge current, i.e., the total planned current flowing, so that it stays within the maximum current value. Alternatively, a warning is issued before the maximum current value is exceeded. Similarly, when charging is stopped, it is checked whether the estimated individual current flowing exceeds the maximum current value, and if so, charging is stopped so that the maximum current value is not exceeded, thereby enabling safe and efficient charging by taking into account imbalances and cross currents in the charging current.

[0093]

[0094] (Flowchart) The procedure by which the control unit 5 of FIG. 1 estimates the individual energization currents using the individual energization current estimation function in the above four state changes will be described with reference to the flowcharts of FIGS. 9 to 14. In the following flowcharts, each parameter is defined as follows: a: Set charge current update time b: Maximum discharge current update time c: Wait time after charging stops d: Wait time after discharging stops e: Wait time after maximum discharge current reduction α: Parallel connection margin increase % β: Set charge current reduction % γ: Charge margin % δ: Set discharge current reduction % ε: Discharge margin % (1: Flow for checking whether connection is possible when connected in parallel) The procedure for checking whether connection is possible when connected in parallel will be described with reference to the flowchart of FIG. 9. Note that in the following flowcharts, some formulas may be omitted for space reasons. Here, we will basically consider the case where the power supply device 100 is connected to a charger CHG for charging, but charging will also be described as appropriate. First, in step S901, the total planned energization current is calculated by all= 0. It is also determined whether parallel connection is possible. Here, the cross current is estimated from the battery voltage and internal resistance of each battery block 1, and it is confirmed that it does not deviate from the maximum current value during charging. In the case of two battery blocks connected in parallel, the positive is for charging and the negative is for discharging, and the determination is made based on (the larger of the current I1 flowing through the first battery block 10 and the current I2 flowing through the second battery block 20) ​​> maximum charging current value - margin. For example, for I1, the determination is made by calculating the following formula.

[0095] [Equation 10] |(R × I all + OCV2 - OCV1) / (R1 + R2) | > Maximum charging current value - margin Note that the above formula shows the formula for two battery blocks connected in parallel, but in the case of three or more battery blocks connected in parallel, only battery blocks that can be connected in parallel are connected, and additional connections are made while charging and discharging. Here, all battery blocks that can be connected in parallel are connected in order of lowest voltage for charging, and highest voltage for discharging. On the other hand, battery blocks that cannot be connected are charged and discharged to bring them close to the voltage at which they can be connected before being connected.

[0096] If it is determined in step S901 that the maximum current value during charging will be exceeded, proceed to step b (FIG. 10, details will be described later). On the other hand, if it is determined in step S901 that the maximum current value will not be exceeded, it is determined that parallel connection is possible, so proceed to step S902, where the individual switch units 3 of all battery blocks 1 are switched ON.

[0097] Next, proceed to step S903, where the current passing through each battery block 1 is actually measured to determine whether it is equal to or less than the maximum current value. Here, it is determined whether (maximum current of the individual current passing through each battery block 1)>(maximum current value during charging - margin). Then, if the actually measured individual current passing through each battery block 1 exceeds the maximum current value during charging, the margin is increased. Specifically, if the answer is YES in step S90, i.e., if the maximum current value is exceeded, proceed to step S904, where the individual switch units 3 of all battery blocks 1 are switched OFF. Then, in step S905, the margin is increased by α%, and the process returns to step S901, where the above process is repeated. On the other hand, if the answer is NO in step S903, i.e., if the current is equal to or less than the maximum current value, proceed to step d (FIG. 12, details will be described later).

[0098] Next, a case where it is determined in step S901 of Fig. 9 that the maximum current value during charging will be exceeded and the process proceeds to step b will be described with reference to Fig. 10. First, in step S1001, a notification is issued that parallel connection is not possible. Next, in step S1002, a determination is made as to whether to discharge or charge. If discharging is to be performed, the process proceeds to step c (Fig. 11, details will be described later). On the other hand, if charging is to be performed, the process proceeds to step S1003, where a check is made to see if additional battery block 1 connections are possible while the power supply device 100 is charging.

[0099] (3: Flow for checking whether an additional connection is possible while the power supply device 100 is in use (charging)) The following describes the procedure for checking whether an additional connection is possible while the power supply device 100 is in use (here, charging). First, in step S1003, a battery block 1 with a low closed circuit voltage is extracted from among the multiple battery blocks 1, and it is determined whether this battery block 1 is chargeable. Here, the closed circuit voltage, battery temperature, etc. are referenced. If it is determined that charging is not possible, the process proceeds to step S1004, where a notice that charging is not possible is sent, and the process ends. On the other hand, if it is determined that charging is possible, the process proceeds to step S1005, where the individual switch unit 3 of the battery block 1 with the low voltage is switched ON. Then, the process proceeds to step S1006, where charging is started at the maximum charging current of the battery block 1. Next, the process proceeds to step S1007, where it is determined whether the additional battery block is chargeable, and if not, the process jumps to step S1004, where a notice that charging is not possible is sent, and the process ends. On the other hand, if it is determined that the additional battery block can be charged, the process proceeds to step S1008, where the estimated individual current flow after connection is estimated from the battery voltage, internal resistance value, and current of each battery block 1, and it is confirmed whether the potential difference is such that the battery blocks 1 can be connected in parallel. all = 0, and n = 1 is the additional battery block, and then the following equation is calculated to make the determination.

[0100] [Equation 11] |I1 = (R2 × I all + (CCV2-Ib2×Ri2)-OCV1) / (R1+R2) |> (Maximum current value during charging - margin) | I2 = (R1×I all +OCV1-(CCV2-Ib2×Ri2)) / (R1+R2)|>(maximum current value during charging-margin) If the above formula is satisfied, the process of step S1008 is repeated until the above formula is no longer satisfied. In other words, charging continues and waits until the above formula is no longer satisfied. Then, when the above formula is no longer satisfied, the process proceeds to step S1009, where charging is stopped. This completes charging until the corresponding battery block 1 is in a state where it can be connected in parallel. Then, the process proceeds to step S1010, where after charging is stopped, the process waits until the voltage stabilizes. Here, it waits for c seconds to pass. Then it returns to a (FIG. 9). Note that instead of this procedure, additional connections may be made while charging is continuing without stopping the charging.

[0101] (3: Flow for checking whether additional battery blocks can be connected in parallel while in use (discharging)) On the other hand, if the result of step S1002 in Fig. 10 is NO, i.e., if it is determined that discharging is to be performed, the process proceeds to Fig. 11. Here, it is checked whether additional battery blocks can be connected in parallel while in use (charging).

[0102] First, in step S1101, it is determined whether or not the battery block 1 with the highest closed circuit voltage among the multiple battery blocks 1 is capable of discharge. This determination is made by referring to the closed circuit voltage, battery temperature, etc. As a result, if it is determined that the battery block 1 with the highest closed circuit voltage is not capable of discharge, the process proceeds to step S1102, a notification is issued that discharge is not possible, and the process ends. On the other hand, if it is determined in step S1101 that the battery block 1 with the highest closed circuit voltage is capable of discharge, the process proceeds to step S1103, and the individual switch unit 3 of the battery block 1 with the highest closed circuit voltage is switched ON. Then, the process proceeds to step S1104, and discharge begins. Then, in step S1105, it is determined whether or not the battery block to be added is capable of discharge. If it is determined that discharge is not possible, the process proceeds to step S1102, a notification is issued that discharge is not possible, and the process ends.

[0103] On the other hand, if it is determined that discharge is possible, the process proceeds to step S1106, where it is determined whether or not discharge at the time of additional connection can be stopped. If it is determined that discharge can be stopped, the process proceeds to step S1107, where the estimated individual current flow after parallel connection is estimated from the battery voltage, internal resistance value, and current of each battery block 1, and it is confirmed whether the potential difference is such that parallel connection is possible. Specifically, first, the total planned current flow is calculated as I all = 0, and n = 1 is the additional battery block, and then the determination is made by calculating the following formula.

[0104] [Equation 12] |I1 = (R2 × I all + (CCV2-Ib2×Ri2)-OCV1) / (R1+R2) |> (Maximum current value during charging - margin) | I2 = (R1×I all+OCV1-(CCV2-Ib2×Ri2) / (R1+R2)|>(maximum current value during charging-margin) If the above formula is satisfied, the process of step S1107 is repeated until the above formula is no longer satisfied. In other words, discharge continues and standby is performed until the above formula is no longer satisfied. Then, when the above formula is no longer satisfied, the process proceeds to step S1108, where the suspension of discharge is stopped. This completes the discharge until the corresponding battery block 1 is in a state where it can be connected in parallel. Then, the process proceeds to step S1109, where after the discharge is stopped, the process waits until the voltage stabilizes. Here, it waits for d seconds to elapse. Then it returns to a (FIG. 9).

[0105] On the other hand, if the result of determining whether or not the additional battery block can be discharged in step S1106 is "no," the process proceeds to step S1110, where the estimated individual current flowing after parallel connection is estimated from the battery voltage, internal resistance value, and current of the additional battery block, and it is confirmed whether the potential difference is such that parallel connection is possible. Specifically, first, the total expected current flowing is calculated as I all = 0, and n = 1 is the additional battery block, and then the determination is made by calculating the following equation: |I1 = (R2 × I all + (CCV2-Ib2×Ri2)-OCV1) / (R1+R2) |> Maximum charging current value - margin | I2 = (R1×I all +OCV1-(CCV2-Ib2×Ri2) / (R1+R2)|>Maximum charging current value-margin The above is the maximum charging current value, and the maximum discharging current value is also determined using the following formula with n=1 as the additional battery. |I1=(R2×I all + (CCV2-Ib2×Ri2)-OCV1) / (R1+R2) |> Maximum discharge current value - margin | I2 = (R1×I all +OCV1-(CCV2-Ib2×Ri2) / (R1+R2)|>Maximum discharge current value-Margin If both of the above formulas are satisfied, the process of step S1110 is repeated until the above formulas are no longer satisfied. In other words, discharge or discharge is continued and standby is performed until the above formulas are no longer satisfied. Then, when the above formulas are no longer satisfied, the process proceeds to step S1111, where the individual switch of the additional battery block is turned ON. Then, the process proceeds to step S1303 in FIG. 13, which will be described later.

[0106] (2: Current Setting Flow During Charging) Next, the procedure for setting the current during charging / discharging (here, charging) when the measured individual current flowing through the battery is equal to or less than the maximum current value during charging in step S903 of FIG. 9 will be described with reference to FIG. 12. First, in step S1201, it is determined whether the battery is discharging or charging. In this case, the battery is charging, so the process proceeds to step S1202. If the battery is discharging, the process proceeds to step e (FIG. 13, described below).

[0107] In step S1202, it is determined whether charging is possible. Here too, this determination is made based on the closed circuit voltage, battery temperature, etc. If it is determined that charging is not possible, the process proceeds to step S1203, where a notice that charging is not possible is issued and the process ends. On the other hand, if it is determined that charging is possible, the process proceeds to step S1204, where the charging current is estimated from the battery voltage, internal resistance, current, etc. of each battery block 1. Here, the total planned current flowing through the rechargeable battery is calculated. Specifically, the total planned current flowing through the rechargeable battery is calculated so that the following equation is established: all Set.

[0108] [Equation 13] |(R × I all +CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2)|=(maximum current value during charging-margin) Then, the process proceeds to step S1205, and the set total planned current I all Charging is started. Furthermore, in step S1206, the individual energization current is monitored. Specifically, it is monitored to see if (maximum current of the individual energization current of each battery block 1)>(maximum current value during charging-margin). If the actually measured individual energization current exceeds the maximum current value, the margin is increased. Specifically, if the conditional expression in step S1206 is met, the process proceeds to step S1207, where the charging current is reduced by β% and / or the margin is increased by γ%, and the process returns to step S1206.

[0109] Charging continues in this manner, and the set charging current is updated every set time. That is, when a seconds have passed without the state of step S1206 (step S1208), it is determined in step S1209 whether charging is complete. If not, the process returns to step S1204 and the above steps are repeated. If it is determined in step S1209 that charging is complete, the process proceeds to step S1210, where charging is considered complete and the process ends.

[0110] (2: Current Setting Flow During Discharge) On the other hand, if it is determined in step S1201 of FIG. 12 that discharging is to occur, the process proceeds to e, where current setting for charging and discharging (discharging in this case) is performed. This procedure will be described with reference to FIG. 13. First, in step S1301, it is determined whether or not discharging is possible. If it is determined that discharging is not possible, the process proceeds to step S1302, where a notice that discharging is not possible is sent, and the process ends.

[0111] On the other hand, if it is determined in step S1301 that discharge is possible, the process proceeds to step S1303, where the discharge current is estimated from the battery voltage, internal resistance, current, etc. of each battery block 1. Here, the total planned current during discharge is calculated. Specifically, the total planned current I is calculated so that the following equation is satisfied: all Set.

[0112] [Equation 14] |(R × I all +CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2)|=(allowable discharge current-margin) Then, the process proceeds to step S1304, and the set total expected current I all Discharge is started at . Furthermore, in step S1305, the individual current flow is monitored. Specifically, it is monitored to see if (maximum current of the individual current flow of each battery block 1)>(maximum current value during discharge-margin). If the actually measured individual current flow exceeds the maximum current value, the margin is increased. Specifically, if the conditional expression in step S1305 is met, the process proceeds to step S1306, where the maximum discharge current is reduced by δ% and / or the margin is increased by ε%, and the process returns to step S1305.

[0113] Discharge continues in this manner, and the set discharge current is updated every set time. That is, when b seconds have passed without a state corresponding to step S1405 (step S1307), step S1308 determines whether or not the discharge stop voltage has been reached. If it is determined that the discharge stop voltage has been reached, the process proceeds to step S1309, where discharge is stopped and processing ends. On the other hand, if the discharge stop voltage has not been reached, the process proceeds to step S1310, where it is determined whether or not to stop discharge. If the discharge stop condition has not been reached, the process returns to step S1303 and repeats the above process. If it is determined in step S1309 that discharge should be stopped, the process proceeds to step f (FIG. 14, described below).

[0114] (4: Flow before Discharge Stop) Finally, the procedure for stopping discharge when it is determined in step S1309 of FIG. 13 that discharge should be stopped will be described with reference to FIG. 14. First, in step S1401, it is confirmed whether the cross current at the time of stopping discharge exceeds the maximum current value during charging based on the battery voltage, internal resistance, current, etc. of each battery block 1. Specifically, the total planned current I all = 0, and then it is determined whether the following equation is true.

[0115] [Equation 15] |I1 = (CCV2 - CCV1 + Ib1 x Ri1 - Ib2 x Ri2) / (R1 + R2) | > (maximum current value during charging - margin) If the above formula is not true, the cross current will not exceed the maximum current value even if discharging is stopped, so the process proceeds to step S1402, where discharging is stopped and processing ends. On the other hand, if the above formula is true, the cross current when discharging is stopped will exceed the maximum current value during charging, and a warning is issued. Specifically, the process proceeds to step S1403, where a warning is issued that the balance of the internal resistance values ​​of the battery block 1 has been lost. Then, the process proceeds to step S1404, where the maximum discharge current is reduced within a range that does not exceed the maximum current value during discharge. Specifically, the total planned current flow I is set so that the following formula is true. all Set.

[0116] [Equation 16] |I1 = (R2 × I all+CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2)|=(maximum current value during charging-margin) Note that step S1404 is for cases where it is not necessary to immediately stop discharging. On the other hand, if it is necessary to immediately stop discharging, the discharging is stopped immediately without going through the step of gradually reducing the discharge current as in step S1404. Even in this case, the advantage of issuing a warning in step S1403 can be obtained.

[0117] Discharge continues in this manner, and it is checked at each set time whether the cross current at the time of discharge stop exceeds the maximum current value during charging. That is, after e seconds have elapsed (step S1405), the process returns to step S1401 and repeats the above process. In this manner, if it is determined in step S1401 that the cross current will not exceed the maximum current value even if discharge is stopped, the process proceeds to step S1402, where discharge is stopped and safely terminated.

[0118] While the above describes an example in which the battery block 1 is a two-parallel configuration consisting of a first battery block 10 and a second battery block 20 as shown in Figure 1, the present disclosure is not limited to this configuration and can also be applied to cases in which three or more battery blocks are connected in parallel. In the case of three or more parallel connections, 1: When connecting in parallel, only battery blocks that can be connected in parallel are connected. For example, if charging, connect the battery block with the lowest voltage first, and if discharging, connect the battery block with the highest voltage first. Then, 2: Set the charging and discharging current, and 3: Check whether additional connections are possible during use.

[0119] [Embodiment 2] While Figure 2 above illustrates a power supply device in which a first battery block and a second battery block are connected in parallel, and a third battery block is added in parallel, the present disclosure is not limited to this configuration and can also be applied to a configuration in which a second battery block is added in parallel to the first battery block, or an added second battery block is removed. Even in such cases, cross currents may occur, so the power supply device and its current control method described above can be applied to prevent the cross current from exceeding the specified maximum current value. Such an example is shown in Figure 15 as a power supply device according to embodiment 2. In this figure, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions are omitted where appropriate.

[0120] 15 includes a main conduction path MLN, an overall current detection unit 6, an overall switch unit 7, a first battery block 10, a first switch unit 13, a first current detection unit 12, and a control unit 5. The power supply device 200 also includes connection terminals for connecting a second battery block 20 in parallel with the first battery block 10. The second battery block 20 has a second switch unit 23 and a second current detection unit 22 connected in series. Even in this power supply device 200, cross currents can occur during parallel connection or separation depending on the state of the first battery block 10 and the second battery block 20, such as their internal resistance values ​​and line resistance values. Therefore, when the power supply device 200 detects a state change such as connection or disconnection of the second battery block 20, the control unit 5 estimates the first estimated current I1 and the second estimated current I2 that will flow through the first battery block 10 and the second battery block 20 after the state change before executing the state change, and allows the state change if each does not exceed the maximum current value, or takes necessary measures such as reducing the total planned current Iall if they do exceed the maximum current value.

[0121] In the above example, the control unit 5 determines the total energization current. However, the present disclosure is not limited to this configuration, and the determination of the total energization current may be performed by another component. For example, the control unit may communicate with an external device, collect and transmit parameters such as estimated individual energization currents, and have an external server or cloud calculate the total energization current, receive the calculation result, and perform control based on the calculation result.

[0122] As described above, the present disclosure provides a power supply device capable of highly efficient charging and discharging even when there is an imbalance between battery blocks. In particular, cross currents can be estimated from the CCV, internal resistance, and current immediately before estimation, allowing charge and discharge control to address the cross currents. Furthermore, by updating the total charge and discharge current from the estimated individual currents, it is possible to maximize charge and discharge without exceeding the maximum current value, thereby achieving efficient charge and discharge. Additionally, estimating the estimated individual currents and determining the total current when starting or stopping charge and discharge, or when connecting or adding battery blocks during charging and discharging, which are times when cross currents are likely to occur, can improve reliability and safety. Furthermore, providing a margin for each threshold value can address calculation discrepancies due to factors such as deterioration. Furthermore, the margin can be updated based on actual measurements.

[0123] In the above example, the power supply device 100 is attached to the electrical device LOD to be driven and supplies power to the electrical device LOD. The power supply device is also connected to a charger CHG to charge the battery block. When the remaining capacity of a battery block is low or when it has deteriorated, the corresponding battery block may be replaced. Alternatively, a battery block may be added. However, the present disclosure is not limited to power supply devices that house only a battery block, but is also applicable to configurations in which a battery block is housed within the housing of an electrical device. In the present disclosure, a power supply device that houses a battery block within a housing such as a case is sufficient, and a power supply device that incorporates a driving battery block within the housing of the electrical device itself is also referred to as a power supply device. In other words, the present disclosure is not limited to replaceable power supply devices, but can also be applied to electrical devices with built-in battery blocks. Similarly, chargers are not limited to external configurations, and include power supply devices that incorporate the charger itself.

[0124] The power supply device according to the present disclosure can be suitably used as a stationary power storage device, for example, a power supply device for home use, business use, or factory use, or as a backup power supply for a server. It can also be used as a power source for driving assisted bicycles, and a power source for vehicles such as self-propelled delivery robots, electric carts for delivery and golf courses, electric scooters, construction machinery, hybrid vehicles, and electric vehicles. It can also be used as a power source for portable electrical devices such as radios, electric cleaners, and power tools. It can also be used not only as a power supply, but also as a cooling mechanism for electrical devices with built-in heating elements.

[0125] DESCRIPTION OF SYMBOLS 100, 200...Power supply device 1...Battery block 2...Individual current detection unit 3...Individual switch unit 4...Individual closed circuit voltage detection unit 5...Control unit 6...Overall current detection unit 7...Overall switch unit 10...First battery block 11...Secondary battery cell 12...First current detection unit 13...First switch unit 14...First closed circuit voltage detection unit 20...Second battery block 22...Second current detection unit 23...Second switch unit 24...Second closed circuit voltage detection unit 30...Third battery block 32...Third current detection unit 33...Third switch unit 34...Third closed circuit voltage detection unit MLN...Main conductive path OUT...External connection terminal SIG...Signal terminal CHG...Charger FT...Charge / discharge element LOD...Electrical equipment

Claims

1. A power supply device comprising: a main conductive path; a first battery block and a second battery block, each having a predetermined maximum current value allowed for charging or discharging, branched from the main conductive path and connected in parallel to each other; a first switch unit connected to the first battery block; a second switch unit connected to the second battery block; and a control unit for controlling opening and closing of the first switch unit and the second switch unit, wherein the control unit estimates a first estimated current I1 flowing through the first battery block and a second estimated current I2 flowing through the second battery block using as input parameters a first closed circuit voltage CCV1, a first energization current Ib1, and a first combined resistance value R1 including an internal resistance value Ri1 of the first battery block, and a second closed circuit voltage CCV2, a second energization current Ib2, and a second combined resistance value R2 including an internal resistance value Ri2 of the second battery block; a state change for starting or stopping charging and / or discharging of either the first battery block or the second battery block by the first switch unit or the second switch unit; a state change for setting a total current flowing through the main conductive path during charging and / or discharging of the first battery block and the second battery block; and a state change for additionally connecting a third battery block in parallel with the first battery block and the second battery block during charging and / or discharging of the first battery block and the second battery block, the power supply device configured to determine whether the estimated first estimated current I1 and the second estimated current I2 are equal to or lower than a maximum current value allowed for charging and discharging, respectively, in response to a request for at least any of the following state changes, and to permit any of the state changes when it is determined that both are equal to or lower than the maximum current value.

2. A power supply device according to claim 1, wherein the control unit is configured to calculate the first estimated current I1 and the second estimated current I2 from the following formula: I1 = (R2 x I all +CCV2-CCV1+Ib1×Ri1-Ib2×Ri2) / (R1+R2) I2=(R1×I all + CCV1-CCV2+Ib2×Ri2-Ib1×Ri1) / (R1+R2) (where I all is the total planned current; I1 is the estimated individual current flowing through the first battery block; Ri1 is the internal resistance value of the first battery block; R1 is a first composite resistance value obtained by adding the internal resistance value Ri1 of the first battery block to the line resistance value Ro1 outside the first battery block; CCV1 is the closed circuit voltage of the first battery block; Ib1 is the individual current flowing through the first battery block before the state change; I2 is the estimated individual current flowing through the second battery block; Ri2 is the internal resistance value of the second battery block; R2 is a second composite resistance value obtained by adding the internal resistance value Ri2 of the second battery block to the line resistance value Ro2 outside the second battery block; CCV2 is the closed circuit voltage of the second battery block; and Ib2 is the individual current flowing through the second battery block before the state change.

3. A power supply device comprising: a main conductive path; a plurality of battery blocks branching off from the main conductive path and connected in parallel with each other, each having a predetermined maximum current value permitted for charging or discharging; a plurality of individual current detection units connected to each battery block, respectively, for individually detecting a signal related to an individual current flowing through each battery block; a total current detection unit for detecting a signal related to a total current flowing through the main conductive path; and a control unit which estimates an estimated individual current flowing through each of the plurality of battery blocks for a given planned total current flowing through the main conductive path, based on the signals related to the individual currents detected by the plurality of individual current detection units, each internal resistance value of the plurality of battery blocks, and the signal related to the total current detected by the total current detection unit, and determines the total charging or discharging current flowing through the main conductive path such that none of the estimated individual currents exceeds a predetermined maximum current value permitted for charging or discharging of each battery block.

4. A power supply device comprising: a main conductive path; n battery blocks branched from the main conductive path and connected in parallel; n individual current detection units (n≧2) connected to each battery block for individually detecting a signal related to an individual current flowing through each battery block; n individual closed circuit voltage detection units connected to each battery block for individually detecting a signal related to an individual closed circuit voltage of each battery block; a total current detection unit for detecting a signal related to a total current flowing through the main conductive path; and a control unit that estimates an estimated individual current flowing through each of the n battery blocks based on at least one of the signals related to the individual closed circuit voltages detected by the n individual closed circuit voltage detection units, the internal resistance values ​​of the n battery blocks, and the signal related to the total current flowing through the total current detection unit, and determines a total charging or discharging current flowing through the main conductive path such that none of the estimated individual currents exceeds a maximum current value allowed for charging or discharging of each battery block.

5. A power supply device as described in claim 4, wherein the control unit is configured to control, when determining the total charging or discharging current flowing through the main conductive path, such that none of the estimated individual current flows exceeds a maximum current value permitted for charging or discharging of each of the battery blocks, based on a state in which the output voltages of the battery blocks, which reflect the path resistance values ​​of the battery blocks connected in parallel, are calculated to be equal.

6. A power supply device according to claim 4, wherein the control unit is configured to calculate the estimated individual energization current based on the following simultaneous linear equations with 3n unknowns (n≧1): OCV1=CCV1-Ib1×Ri1 OCV2=CCV2-Ib2×Ri2 ... OCV n = CCV n -Ib n ×Ri n VPACK1=OCV1+I1×R1 VPACK2=OCV2+I2×R2... VPACK n = OCV n +I n ×R n I all =I1+I2+...+I n VPACK1=VPACK2=. .. .. =VPACK n (In the above formula, CCV n is the closed circuit voltage of the nth battery block; Ib n is the current flowing through the nth battery block; Ri n is the internal resistance value of the nth battery block; I n is the estimated individual current flow of the nth battery block; VPACK n is the output voltage of the nth battery block before the state change. n is the internal resistance value Ri of the nth battery block n The resistance value Ro of the line outside the nth battery block n The nth composite resistance value obtained by adding all is the total planned current; 7. A power supply device according to any one of claims 1 to 6, further comprising a plurality of individual switch sections connected to each battery block respectively and capable of individually switching the parallel connection ON / OFF.

8. A power supply device according to any one of claims 1 to 6, further comprising a general switch section provided on said main conductive path.

9. A power supply device according to any one of claims 2 to 6, further comprising a charge / discharge element for controlling a total charging or discharging current flowing through said main conductive path in accordance with said estimated individual current flowing through said control unit.

10. A power supply device comprising: a main conductive path; a first battery block branched off from the main conductive path and connected thereto, the first battery block having a predetermined maximum current value permitted for charging or discharging; a first switch unit connected in series with the first battery block; and a control unit for controlling the opening and closing of the first switch unit, wherein the first battery block is branched off from the main conductive path and is connectable in parallel with the first battery block, and the second battery block is capable of controlling the opening and closing of a second switch unit connected in series with the second battery block by the control unit, and the control unit: a first estimated current I1 flowing through the first battery block and a second estimated current I2 flowing through the second battery block when the second battery block is connected to the first battery block, using as input parameters a first combined resistance R1 including a first closed circuit voltage CCV1, a first current flowing current Ib1, and an internal resistance Ri1 of the first battery block of the first battery block, and a second combined resistance R2 including a second closed circuit voltage CCV2, a second current flowing current Ib2, and an internal resistance Ri2 of the second battery block; a state change of either the first battery block or the second battery block being electrically connected or disconnected to the main conductive path; a state change of either the first battery block or the second battery block starting or stopping charging and / or discharging by the first switch unit or the second switch unit; a state change of setting a total current flowing through the main conductive path when charging and / or discharging the first battery block and the second battery block; the power supply device is configured to determine whether the estimated first estimated current I1 and the estimated second estimated current I2 are equal to or less than a maximum current value allowed for charging and discharging in response to a request for at least one of the state changes, and to permit any of the state changes when it is determined that both are equal to or less than the maximum current value.

11. A current control method for a power supply device including a main conductive path; a first battery block and a second battery block, each having a predetermined maximum current value allowed for charging or discharging, branched from the main conductive path and connected in parallel with each other; and a control unit for controlling charging and discharging of the first battery block and the second battery block, comprising the steps of: detecting the occurrence of at least one of the following state changes: a state change of connection or disconnection of either the first battery block or the second battery block; a state change of starting or stopping charging and / or discharging of the first battery block and the second battery block; a state change of setting a total current flowing through the main conductive path during charging and / or discharging of the first battery block and the second battery block; and a state change of additionally connecting a third battery block in parallel with the first battery block and the second battery block during charging and / or discharging of the first battery block and the second battery block; when any of the state changes are detected, estimating a first estimated current I1 estimated to flow through the first battery block after any of the state changes and a second estimated current I2 estimated to flow through the second battery block using as input parameters a first combined resistance value R1 including a first closed circuit voltage CCV1, a first flow current Ib1, and an internal resistance value Ri1 of the first battery block, and a second combined resistance value R2 including a second closed circuit voltage CCV2, a second flow current Ib2, and an internal resistance value Ri2 of the second battery block.

12. A current control method for a power supply device as described in claim 11, further comprising the steps of: determining whether or not the first estimated current I1 and the second estimated current I2 estimated by the control unit are each equal to or less than a permissible maximum current value; and, when it is determined that both the first estimated current I1 and the second estimated current I2 are equal to or less than the maximum current value, executing one of the state changes.

13. A current control method for a power supply device as claimed in claim 11 or 12, wherein the maximum current values ​​include a first maximum charging current value permitted in charging the first battery block, a first maximum discharging current value permitted in discharging the first battery block, a second maximum charging current value permitted in charging the second battery block, and a second maximum discharging current value permitted in discharging the second battery block.

14. A current control method for a power supply device as described in claim 11 or 12, wherein the control unit controls charging and discharging of the first battery block and the second battery block by turning on and off a first switch unit connected to the first battery block and a second switch unit connected to the second battery block.

15. A current control method for a power supply device comprising: a main conductive path; a plurality of battery blocks branching off from the main conductive path and connected in parallel with each other, each having a predetermined maximum current value allowed for charging or discharging; and a plurality of individual current detection units connected to each battery block for individually detecting a signal related to an individual current flowing through each battery block, the method comprising the steps of: detecting a signal related to an individual current by each of the plurality of individual current detection units; estimating, by a control unit, an estimated individual current flowing through each of the plurality of battery blocks for a given total planned current flowing through the main conductive path based on the detected signals related to each individual current and each internal resistance value of the plurality of battery blocks; and determining a total current flowing for charging or discharging to be flowed through the main conductive path such that none of the estimated individual currents exceeds the predetermined maximum current value in each battery block.

16. A current control method for a power supply device including a main conductive path; a first battery block branched off from the main conductive path and connected thereto, the first battery block having a predetermined maximum current value permitted for charging or discharging; and a control unit for controlling charging and discharging of the first battery block, comprising the steps of: detecting, during charging and / or discharging of the first battery block, at least one of the following state changes: a state change in which a second battery block is branched off from the main conductive path and additionally connected in parallel with the first battery block; a state change in which either the first battery block and / or the second battery block is connected or disconnected; a state change in which charging and / or discharging of the first battery block and / or the second battery block is started or stopped; and a state change in which a total current flowing through the main conductive path during charging and / or discharging of the first battery block and / or the second battery block is set; a step of estimating a first estimated current I1 estimated to flow through the first battery block after any of the state changes and a second estimated current I2 estimated to flow through the second battery block, using as input parameters a first combined resistance value R1 including a first closed circuit voltage CCV1, a first energization current Ib1, and an internal resistance value Ri1 of the first battery block of the first battery block, and a second combined resistance value R2 including a second closed circuit voltage CCV2, a second energization current Ib2, and an internal resistance value Ri2 of the second battery block, when any of the state changes are detected; a step of determining whether the first estimated current I1 and the second estimated current I2 estimated by the control unit are each equal to or less than a maximum current value allowed; and a step of executing any of the state changes when it is determined that both of the first estimated current I1 and the second estimated current I2 are equal to or less than the maximum current value.

17. A current control method for a power supply device including a main conductive path; a first battery block and a second battery block, each of which has a predetermined maximum current value allowed for charging or discharging, branched from the main conductive path and connected in parallel to each other; and a control unit for controlling charging and discharging of the first battery block and the second battery block, comprising the steps of: detecting the occurrence of at least one of the following state changes: a state change of connection or disconnection of either the first battery block or the second battery block; a state change of starting or stopping charging and / or discharging of the first battery block and the second battery block; a state change of setting a total current flowing through the main conductive path during charging and / or discharging of the first battery block and the second battery block; and a state change of additionally connecting a third battery block in parallel with the first battery block and the second battery block during charging and / or discharging of the first battery block and the second battery block; and assuming, upon detection of any of the state changes, an assumed total current flowing through the main conductive path after any of the state changes; A current control method for a power supply device, comprising: a step of determining whether a first assumed current assumed to flow through the first battery block and a second assumed current assumed to flow through the second battery block are each equal to or less than a maximum current value allowed based on the assumed assumed total current flow; and a step of executing any of the state changes when it is determined that both the first assumed current and the second assumed current are equal to or less than the maximum current value.

18. A current control method for a power supply device as described in claim 17, wherein, if it is determined in the step of determining whether the first assumed current and the second assumed current are each equal to or less than the maximum current value that either the first assumed current or the second assumed current is greater than the maximum current value, the total conduction current is reduced in a step of assuming an assumed total conduction current, and a step of determining whether the first assumed current and the second assumed current are each equal to or less than a permissible maximum current value based on the assumed assumed total conduction current is performed, and the above steps are repeated until it is determined that both the first assumed current and the second assumed current are equal to or less than the maximum current value.

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