JP2022067494A - Battery cell control device and battery cell control method - Google Patents

Abstract

To provide a battery cell control device that is configured to control a plurality of battery cells, and enables the transition of a battery cell to high rate deterioration to be easily and surly suppressed without obtaining current value and resistance value of all of the plurality of battery cells.SOLUTION: A control device 70 controls the current of a plurality of battery cells 4 that are rechargeable and dischargeable secondary batteries and have different directions. The control device 70 comprises: an identification unit 71 that identifies the battery cell 4 having the highest degree of transition on the basis of the direction of each battery cell 4 to high-rate deterioration; a current setting unit 72 that sets an upper limit current value on the basis of the transition state of the identified battery cell 4 to high rate deterioration; and a current control unit 73 that limits an effective current value of the entire plurality of battery cells 4 to an upstream current value or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device and a control method for controlling currents of a plurality of battery cells.

Conventionally, in a battery cell which is a rechargeable secondary battery used in an electric vehicle or a hybrid vehicle, the internal resistance of the battery cell is temporarily (that is, reversible) due to continuous charging / discharging (cycle) by a large current (high rate). A phenomenon that rises to the target), so-called high-rate deterioration (or high-rate cycle deterioration), may occur. When high-rate deterioration occurs, it becomes difficult to improve the power consumption rate (electricity cost) of electric vehicles and the like because the effective current that can be charged and discharged from the battery cell cannot be increased.

Therefore, in the battery cell control device described in Patent Document 1, the current value and the voltage value in the battery cell are measured, the internal resistance is calculated from these current values and the voltage values, and the amount of increase in the internal resistance of the battery cell is high-rate. Obtained as the amount of deterioration. When the high rate deterioration amount is equal to or more than a predetermined value, the complete recovery from the high rate deterioration is estimated from the neglected (that is, charge / discharge stop) time, and when it is determined that the high rate deterioration amount is not completely recovered, the charge / discharge amount is usually calculated. Limit more than time, thereby suppressing high rate degradation.

Japanese Unexamined Patent Publication No. 2013-32966

In the battery cell control device described in Patent Document 1 as described above, in a configuration including a plurality of battery cells, the current value and resistance of the individual battery cells are to be detected in order to detect the amount of high rate deterioration for each battery cell. It is necessary to obtain the values sequentially. Therefore, the detection operation of high rate deterioration in the control device becomes complicated, and it becomes difficult to set the optimum effective current that suppresses the transition to high rate deterioration.

The present invention has been made in view of the above circumstances, and in a configuration in which current control of a plurality of battery cells is performed, high-rate deterioration of the battery cells is performed without obtaining the current values and resistance values of all the plurality of battery cells. It is an object of the present invention to provide a battery cell control device capable of easily and surely suppressing the transition to.

The present inventors have discovered that a plurality of battery cells mounted on an electric vehicle or the like have different degrees of high-rate deterioration depending on the arrangement state of the individual battery cells, and the present invention is created based on the findings. I came to do it.

That is, in order to solve the above problems, the battery cell control device of the present invention is a battery that controls the current of a plurality of battery cells that are rechargeable secondary batteries and have different orientations. Based on a specific unit that identifies a battery cell that is a cell control device and has the highest degree of transition from the orientation of each battery cell to high-rate deterioration, and a state of transition of the identified battery cell to high-rate deterioration. It is characterized by including a current setting unit for setting an upper limit current value and a current control unit for limiting the effective current value of the entire plurality of battery cells to the upstream current value or less.

According to such a configuration, the specific unit identifies the cell having the largest degree of transition from the orientation of each battery cell to the high rate deterioration from among the plurality of battery cells. Then, the current setting unit sets the upper limit current value based on the transition state of the specified battery cell to the high rate deterioration. The current control unit limits the effective current value of the entire plurality of battery cells to the upstream current value or less. As a result, in a configuration in which current control of a plurality of battery cells is performed, it is possible to easily and surely suppress the transition to high-rate deterioration of the battery cells without obtaining the current value and the resistance value of all the plurality of battery cells. Become.

In the above battery cell control device, the battery cell has a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet and impregnated with an electrolytic solution. When the direction in which the electrolytic solution is most likely to flow during charging / discharging of the battery cell in the plane of the separator is defined as the first flow direction, the specific portion refers to the first flow of the two battery cells. It is preferable to specify a battery cell having a small angle between the direction and the vertical direction as a battery cell having a large degree of transition to high-rate deterioration.

Of the two battery cells, the battery cell in which the angle between the first flow direction and the vertical direction, in which the electrolytic solution is most likely to flow in the plane of the separator during charging and discharging, is small, is due to the influence of gravity inside the battery cell. It tends to be biased in the first flow direction, and the ion concentration distribution between the poles is biased, so that high rate deterioration tends to occur (that is, the degree of transition to high rate deterioration is large). Therefore, according to the above configuration, of the two battery cells, the battery cell having a small angle between the first flow direction and the vertical direction is a battery cell having a large degree of transition to high-rate deterioration. By identifying the presence, it becomes possible to reliably perform current control based on the battery cell, which tends to deteriorate at a high rate.

In the above battery cell control device, the battery cell has a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet and impregnated with an electrolytic solution. The direction in which the electrolytic solution is most likely to flow during charging / discharging of the battery cell in the plane of the separator is defined as the first flow direction, and the direction orthogonal to the first flow direction in the plane of the separator is the first. When defined as two flow directions, the specific portion refers to a battery cell having a small angle between the second flow direction and the vertical direction among the two battery cells and having a large degree of transition to high-rate deterioration. It is preferable to specify that.

Of the two battery cells, the battery cell having a small angle between the second flow direction orthogonal to the first flow direction in which the electrolytic solution is most likely to flow and the vertical direction is lower in the second flow direction in the plane of the separator. The electrolytic solution tends to accumulate on the side closer to the direction, and the ion concentration distribution between the poles is biased, so that high-rate deterioration tends to occur (that is, the degree of transition to high-rate deterioration is large). Therefore, according to the above configuration, the specific part is a battery cell having a small angle between the second flow direction and the vertical direction among the two battery cells and having a large degree of transition to high rate deterioration. By specifying it, it becomes possible to reliably perform current control based on the battery cell, which tends to deteriorate at a high rate.

The battery cell control device further includes a binding force applying unit that applies a binding force to the plurality of battery cells in a compression direction, and a binding force control unit that controls the binding force applying unit. When the deterioration evaluation value indicating the state of transition to high-rate deterioration in the battery cell having the highest degree of transition to high-rate deterioration is smaller than a predetermined value, the power control unit suspends charging / discharging of the plurality of battery cells. During this period, it is preferable to control the binding force applying portion so as to weaken the binding force on the battery cell.

The present inventors have experimentally found that if the binding force of the battery cells is weakened while the charging / discharging of the plurality of battery cells is suspended, the recovery from the high rate deterioration of the battery cells is accelerated. Therefore, according to the above configuration, while the plurality of battery cells are inactive from charging / discharging, the binding force applying portion weakens the binding force of the battery cells, thereby accelerating the recovery from the high rate deterioration of the battery cells. Will be possible.

In the above-mentioned battery cell control device, in a configuration in which the plurality of battery cells are linearly arranged along a predetermined arrangement direction, the binding force applying portion is transferred from the predetermined arrangement direction to each of the battery cells. Further, a bus bar that applies a binding force at the same time and connects the battery cells is further provided, and the bus bar is in the predetermined arrangement direction when the plurality of battery cells receive the binding force from the predetermined arrangement direction. It is preferable to have an easily deformable portion that deforms in a direction in which the length changes.

According to such a configuration, the bus bar connecting the battery cells has an easily deformable portion, and the easily deformable portion has a length in the predetermined arrangement direction when a plurality of battery cells are bound from a predetermined arrangement direction. Transforms in the direction of change. As a result, even if the distance between the battery cells is deformed due to a change in the binding force applied to the battery cells, it is possible to easily maintain the electrical connection between the battery cells without a load.

The battery cell control method of the present invention is a battery cell control method for controlling currents of a plurality of battery cells which are rechargeable secondary batteries and have different orientations, and is the individual battery cell control method. A specific step of specifying the battery cell having the highest degree of transition from the orientation of the battery cell to high rate deterioration, a current setting step of setting an upper limit current value based on the specified transition state of the battery cell to high rate deterioration, and a current setting step. It is characterized by including a current control step of limiting the effective current value of the entire plurality of battery cells to the upstream current value or less.

According to such a feature, in the specific step, the cell having the largest degree of transition from the orientation of each battery cell to the high rate deterioration is specified from among the plurality of battery cells. Then, in the current setting step, the upper limit current value is set based on the transition state of the specified battery cell to the high rate deterioration. Then, in the current control step, the effective current value of the entire plurality of battery cells is limited to the upstream current value or less. As a result, when controlling the current of a plurality of battery cells, it is possible to easily and surely suppress the transition to high-rate deterioration of the battery cells without obtaining the current values and resistance values of all the multiple battery cells. Become.

According to the battery cell control device and control method of the present invention, in a configuration in which current control of a plurality of battery cells is performed, the high rate deterioration of the battery cells can be achieved without obtaining the current value and the resistance value of all the plurality of battery cells. The transition can be easily and reliably suppressed.

It is a perspective view which shows the whole structure of the hybrid vehicle which provided the control device of the battery cell which concerns on 1st Embodiment of this invention. It is a perspective explanatory view of the battery of FIG. It is an exploded perspective view of the electrode winding body inside the battery cell of FIG. It is explanatory drawing which shows the arrangement of the battery cell of FIG. (B) is an arrangement in which both the first flow direction and the second flow direction face the horizontal direction, and (c) is an arrangement in which the first flow direction faces the vertical direction and the second flow direction faces the horizontal direction. It is a graph which shows the time change of the resistance increase rate with respect to the battery cells of arrangements A to C shown in FIGS. 4A to 4C. It is a graph which showed the permissible value of the high rate cycle of a battery cell from the continuous time and the effective current. It is a flowchart which shows the basic current control method for suppressing the high rate deterioration of a battery cell in this invention. It is a map which shows the curve of the limit integrated current amount used in the current control method of FIG. It is a flowchart of the current control method which concerns on one Embodiment of the control method of the battery cell of this invention. 9 is a map showing the relationship between the ion bias evaluation value, which is the evaluation value of high rate deterioration used in the current control method of FIG. 9, and the rest time. It is a map which shows the limit integrated current amount value used in the current control method of FIG. It is a graph which shows the time change of the high rate deterioration evaluation value and the effective current of a battery cell which tends to deteriorate at a high rate. It is a graph for demonstrating that the high rate deterioration evaluation value returns only to 0.8 when the rest time of 3 hours elapses and then 3 hours elapses. It is a graph which shows the time change of the resistance increase rate in the case where the binding force with respect to a battery cell is large and the case where the binding force with respect to a battery cell is small while the battery cell is inactive. It is sectional drawing which shows the structure of the restraint imparting part which restrains a plurality of battery cells provided in the control device of the battery cell which concerns on 2nd Embodiment of this invention, (a) is the state before restraint, (b). ) Indicates the state after restraint. It is a flowchart of the current control method of a battery cell in 2nd Embodiment of this invention. 6 is a map showing the relationship between the ion bias evaluation value, which is the evaluation value of high rate deterioration used in the current control method of FIG. 16, and the rest time. It is a graph which shows the recovery degree of the high rate deterioration evaluation value after a rest time, (a) shows the graph in the case of no binding force decrease, (b) shows the graph in the case of having a binding force decrease.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(First Embodiment)
An embodiment of the battery cell control device according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an overall configuration of a hybrid vehicle provided with a battery cell control device according to the first embodiment of the present invention.

The hybrid vehicle 100 shown in FIG. 1 includes wheels 10, 10, an axle 12, an engine 20, a transmission 30, a motor 40, an inverter 50, a battery module (hereinafter referred to as a battery) 60, and a battery 60. It is equipped with a control device 70 that controls current.

The hybrid vehicle 100 is a so-called parallel hybrid vehicle. The engine 20 and the motor 40 function as a drive source for outputting the driving force of the vehicle. In this hybrid vehicle 100, depending on the driving conditions, the engine 20 and the motor 40 may be used alone, or both the engine 20 and the motor 40 may be used. Traveling is realized only by the motor 40.

The engine 20 is connected to the axle 12 via a transmission 30. The engine 20 is, for example, a gasoline engine.

The motor 40 is connected to the axle 12 and is connected to the battery 60 via the inverter 50. The electric power of the battery 60 is converted into AC power by the inverter 50 and then supplied to the motor 40. The motor 40 receives electric power and functions as an electric motor to rotate the axle 12. The motor 40 can also function as a generator by performing a regenerative operation during deceleration. The electricity generated by the motor 40 is charged into the battery 60.

The control device 70 has a configuration for controlling the current of the battery 60 via the inverter 50, and specifically includes a specific unit 71, a current setting unit 72, and a current control unit 73.

The specifying unit 71 identifies the battery cell 4 having the largest degree of transition from the orientation of each battery cell 4 (see FIG. 2) included in the battery 60 to high-rate deterioration. A specific method for specifying the battery cell 4 will be described in detail later.

The current setting unit 72 sets the upper limit current value based on the transition state of the specified battery cell 4 to high rate deterioration. The current control unit 73 limits the effective current value of the entire plurality of battery cells 4 (battery 60) to the upstream current value or less.

As shown in FIG. 2, the battery 60 constitutes one module by accommodating a plurality of battery cells 4 which are rechargeable and dischargeable secondary batteries and have different orientations in the casings 2 and 3. The casing 2 is a rectangular parallelepiped box body extending in the horizontal direction. Inside the casing 2, a plurality of battery cells 4 (4A) are arranged side by side in a predetermined arrangement direction in an upright state. The casing 3 is a flat box body, and is laid down along the bottom plate of the vehicle body. Inside the casing 3, one or more battery cells 4 (4B) are arranged in a lying state (a state along a horizontal plane).

Each battery cell 4 has a flat rectangular parallelepiped housing 5, an electrode winding body 6 housed inside the housing 5, and a positive electrode terminal 7 and a negative electrode terminal 8 provided on the outer surface of the housing 5.

In the battery cell 4A in the upright state, the positive electrode terminal 7 and the negative electrode terminal 8 are lined up in the first horizontal direction X, and the winding axis direction of the electrode winding body 6 also faces the first horizontal direction X. The long side direction of the elliptical cross section faces the vertical direction Z. On the other hand, in the battery cell 4B in the lying state, the positive electrode terminal 7 and the negative electrode terminal 8 are lined up in the first horizontal direction X, and the winding axis direction of the electrode winding body 6 also faces the first horizontal direction X. The long side direction of the elliptical cross section of the body 6 faces the second horizontal direction Y which is orthogonal to the first horizontal direction.

The electrode winding body 6 of the battery cell 4 (specifically, the battery cell 4A in the upright state in FIG. 2) constitutes a lithium ion battery, and specifically, as shown in FIG. 3, a positive electrode sheet. It has 6a, a negative electrode sheet 6b, and a separator 6c interposed between the positive electrode sheet 6a and the negative electrode sheet 6b and impregnated with an electrolytic solution containing a lithium salt. The electrode winding body 6 is formed into a flat roll having a long oval cross section in the vertical direction by winding a laminate of the positive electrode sheet 6a, the separator 6c, and the negative electrode sheet 6b with the first horizontal direction X as the winding axis direction. It was done. The positive electrode sheet 6a is electrically connected to the positive electrode terminal 7 on the outer surface of the housing 5. The negative electrode sheet 6b is electrically connected to the negative electrode terminal 8 on the outer surface of the housing 5.

The battery cell 4 is not in the form of the electrode winding body 6 in which the laminated body of the positive electrode sheet 6a, the separator 6c, and the negative electrode sheet 6b is wound up, but in the form in which the laminated body is repeatedly laminated many times. May be good.

The positive electrode sheet 6a is obtained by applying, for example, a positive electrode active material and an auxiliary agent to a metal current collector such as an aluminum foil. The negative electrode sheet 6b is obtained by applying a negative electrode active material and an auxiliary agent to a metal current collector such as a copper foil. The separator 6c is made of a porous film and is impregnated with an electrolytic solution.

The electrolytic solution is, for example, a lithium salt dissolved in a non-aqueous solvent. Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC) and butylene carbonate (BC), and chains such as diethyl carbonate (DEC), ethylmethyl carbonate (EMC) and dimethyl carbonate (DMC). Cyclic carboxylic acid esters such as carbonic acid esters, γ-butyrolactone (GBL), and γ-valerolactone (GVL) are used. As the non-aqueous solvent, one type may be used alone, or two or more types may be used in combination.

The direction in which the electrolytic solution flows and the position in which the electrolytic solution is accumulated change depending on the orientation in which the battery cell 4 is arranged. Specifically, the battery cells 4 in the arranged state shown in FIGS. 4A to 4C will be considered.

In the battery cells 4 shown in FIGS. 4A to 4C, the electrolytic solution is most likely to flow along the in-plane of the separator 6c during charging / discharging in the direction along the winding axis direction of the electrode winding body 6. Therefore, in FIGS. 4A to 4C, the direction in which the electrolytic solution is most likely to flow (in the present embodiment, the winding axis direction) is defined as the first flow direction A1. Further, the direction orthogonal to the first flow direction A1 in the plane of the separator 6c (in the present embodiment, the long side direction of the elliptical cross section of the electrode winding body 6) is defined as the second flow direction A2.

Therefore, it can be seen that the battery cells 4 shown in FIGS. 4A to 4C have the following three different arrangements. Specifically, FIG. 4A shows the arrangement of the battery cells 4A in the upright state (arrangement A), and specifically, the first flow direction A1 in which the electrolytic solution easily flows is the first horizontal direction X. The second flow direction A2 orthogonal to the first flow direction A1 faces the vertical direction Z. FIG. 4B shows the arrangement of the battery cells 4B in the lying state (arrangement B), and both the first flow direction A1 and the second flow direction A2 face the horizontal direction. Specifically, the first flow direction A1 faces the first horizontal direction X, and the second flow direction A2 faces the second horizontal direction Y orthogonal to the first horizontal direction X. FIG. 4C shows the arrangement of the battery cells 4C in a state of being erected sideways (arrangement C), in which the first flow direction A1 faces the vertical direction Z and the second flow direction A2 faces the second horizontal direction Y.

In the battery cells 4A to 4C of the three different arrangements (arrangement A) to (arrangement C) shown in FIGS. 4A to 4C, the electrolytic solution accumulates downward B in a state where charging / discharging is suspended. The position to go is different. Among these battery cells 4A to 4C, in the battery cell 4B in the lying state (arrangement B) shown in FIG. 4B, the position where the electrolytic solution is accumulated in the downward direction B is the widest range. The battery cell 4B can suppress the bias of the electrolytic solution in the battery cell 4 most. Further, in the battery cell 4A in the upright state (arrangement A) shown in FIG. 4A, the position where the electrolytic solution is accumulated in the downward direction B is in the same direction as the first flow direction A1 in which the electrolytic solution is most likely to flow. The range extends along the battery cell 4A, and the battery cell 4A can suppress the bias of the electrolytic solution in the battery cell 4 to some extent. In the battery cells 4C in the sideways standing state (arrangement C) shown in FIG. 4C with respect to these battery cells 4B and 4A, the position where the electrolytic solution accumulates in the downward direction B is the most flowing of the electrolytic solution. It is considered that the range extends along the orthogonal direction (second flow direction A2) at the end (lower end) in the easy first flow direction A1, and the bias of the electrolytic solution in the battery cell 4 is the largest in the battery cell 4C. ..

As described above, in the battery cells 4A to 4C of the three different arrangements (arrangement A) to (arrangement C) shown in FIGS. 4A to 4C, the positions where the electrolytic solution is accumulated in the downward direction B are located. It is considered that the internal resistance is different because they are different from each other.

From this point of view, the rate of increase in internal resistance (resistance increase rate) of each of the battery cells 4A to 4C of the three different arrangements (arrangement A) to (arrangement C) shown in FIGS. 4A to 4C. The result of examining the temporal change of Rθ) is shown in the graph of FIG.

Looking at the graph of FIG. 5, the degree of increase in the resistance increase rate Rθ of the battery cell 4B in the lying state (arrangement B) is the lowest, and then the resistance increase rate Rθ of the battery cell 4A in the upright state (arrangement A). The degree of increase is low. On the other hand, it can be seen that the degree of increase in the resistance increase rate Rθ of the battery cell 4C in the state of being erected sideways (arrangement C) is the largest.

High-rate deterioration is a phenomenon in which the internal resistance of a battery cell temporarily (that is, reversibly) increases due to continuous charging / discharging (cycle) due to an excessive current (high rate). Looking at the results of FIG. 5, it is found that the ease of high-rate deterioration (that is, the magnitude of the same degree of transition to high-rate deterioration) differs depending on the orientation of the battery cell 4.

Therefore, the present inventors specify the battery cell 4 in which the high rate deterioration is most likely to occur from the direction of the battery cell 4, set the upper limit current value based on the specified battery cell 4, and refer to the battery cell 4 of the entire battery 60. The present invention was created with the idea that high-rate deterioration can be suppressed by controlling the current based on the upper limit current value.

The above-mentioned "upper limit current value" is an upper limit current value at which high rate deterioration does not occur, and is defined as an allowable value for a high rate cycle (that is, a cycle of charge / discharge with a large current). FIG. 6 shows a graph showing the permissible value of the high rate cycle of the battery cell 4 from the continuous time t (h) and the effective current Ie (A). Looking at the graph of FIG. 6, the permissible value of the high rate cycle is uniquely determined from the continuous time t and the effective current Ie, and is shown on the line along the curve Hs. For example, the effective current is 80 A for 3 hours of continuous time, 60 A for 6 hours, 40 A for 16 hours, and 20 A for 48 hours or more.

In the basic control method of high-rate deterioration (high-rate cycle deterioration), the high-rate deterioration evaluation value is sequentially estimated based on the effective current value and the integrated amount of the critical current at the time of charging / discharging, and the effective current is limited. Specifically, it is executed according to the control flowchart of FIG.

In the flowchart shown in FIG. 7, first, the effective current of the battery cell 4 at a predetermined time interval ΔT is detected during traveling (charging / discharging) of the hybrid vehicle (step S1). Then, the control device 70 (see FIG. 1) determines whether or not the effective current is larger than the predetermined value (step S2).

If the effective current is larger than the predetermined value, the process proceeds to step S3, the limit integrated current value is acquired from the map, and then the high rate cycle (deterioration) evaluation value N is calculated using the effective current value (step S4). On the other hand, if the effective current is smaller than the predetermined value, steps S3 and S4 are skipped and the process proceeds to step S5.

Specifically, as for the method of obtaining the limit integrated current value in step S3, first, the effective current value (for example, 80A) is input to the map showing the curve of the limit integrated amount in FIG. 8, and the effective current value (80A) is used. The integrated current value (239Ah) on the corresponding curve is obtained as the limit integrated current value.

In step S4, the high rate deterioration evaluation value N is set as follows (Equation 1) from the effective current value Ie (A), the elapsed time t (seconds), and the limit integrated current value IS (Ah) obtained in step S3. Is required.
N = 1- (Ie × t / 3600) / IS (Equation 1)
For example, if the effective current value Ie is 80 A, the elapsed time t is 10 seconds, and the limit integrated current value IS is 239 Ah in the above (Equation 1), the high rate deterioration evaluation value N becomes.
N = 1- (80 × 10/3600) /239=0.999073
Is required.

Then, it is determined whether or not the high rate deterioration evaluation value N is larger than the target value (step S5).

If the high rate deterioration evaluation value N is larger than the target value, the process proceeds to step S6, and the high rate deterioration evaluation value N is recorded in the control device 70.

On the other hand, if the high rate deterioration evaluation value N is smaller than the target value, the process proceeds to step S7, and after limiting the high rate deterioration evaluation value N to a predetermined value or less, the process proceeds to step S6.

This makes it possible to limit the effective current of the battery cell 4 that easily deteriorates at a high rate and suppress the deterioration at a high rate.

Next, the flow of the current control method according to the embodiment of the battery cell control method of the present invention will be described with reference to the flowchart shown in FIG.

The current control method of the present embodiment basically includes the following three steps (i) to (iii).
(I) A specific step of identifying the battery cell 4 having the largest degree of transition from the orientation of each battery cell 4 to high rate deterioration.
(Ii) A current setting step of setting an upper limit current value based on the transition state of the specified battery cell 4 to high rate deterioration.
(Iii) A current control step that limits the effective current value of the entire plurality of battery cells 4 to the upstream current value or less.

In the current control method of the present embodiment, first, as a pre-operation before the start, the specific unit 71 (see FIG. 1) of the control device 70 previously performs the battery cell 4 with respect to the plurality of battery cells 4 included in the battery 60. The battery cell 4 in which high-rate deterioration is most likely to occur is specified from the orientation (specific step).

Specifically, the specific unit 71 is the position of the electrical connection portion to which the plurality of battery cells 4 included in the battery 60 are connected, or the type of the casings 2 and 3 (see FIG. 2) in which the plurality of battery cells 4 are accommodated. From the above, it is automatically determined whether the orientation of the battery cell 4 is, for example, the orientation shown in FIGS. 4A to 4C. Then, the specific unit 71 is in a state of being erected next to the battery cell 4 (for example, FIG. 4C) having the largest degree of transition from the determined orientation of the battery cell 4 to the high rate deterioration (most likely to cause the high rate deterioration). Battery cell 4C) is specified.

Here, the specific unit 71 is a two battery cells 4 in the battery cells 4 shown in FIGS. 4A to 4C (for example, a battery cell 4A in FIG. 4A and a battery cell in FIG. 4C). Of the 4C), the battery cell 4 having a small angle between the first flow direction A1 where the electrolytic solution easily flows and the vertical direction Z has a large degree of transition to high-rate deterioration (prone to high-rate deterioration). Specifically, it is specified as the battery cell 4C) of FIG. 4 (c).

Further, the specific unit 71 is a battery cell 4 in the battery cells 4 shown in FIGS. 4A to 4C (for example, a battery cell 4A in FIG. 4A and a battery cell 4B in FIG. 4B). ), The battery cell 4 having a small angle between the second flow direction A2 and the vertical direction Z has a large degree of transition to high-rate deterioration (specifically, FIG. 4). It is specified that it is the battery cell 4A) of (a).

The specific unit 71 derives from the above two specific results that the order of the degree of transition to high rate deterioration (easiness of high rate deterioration) is battery cell 4C, battery cell 4A, and battery cell 4B. , The battery cell 4C having the largest degree of transition to high-rate deterioration (most likely to cause high-rate deterioration) is specified.

In the flowchart shown in FIG. 9, the operation is started by turning on the ignition of the hybrid vehicle (IG-ON).

In step S11, the control device 70 (see FIG. 1) detects the worst high rate deterioration evaluation value N during the previous running (that is, between the previous IG-ON and IG-OFF). Specifically, the battery cell 4 (for example, the battery cell 4C in a state of being erected beside FIG. 4C), which is most likely to deteriorate at high rate, is specified in advance by the specific unit 71 of the control device 70 before the start. As the deterioration evaluation value indicating the transition state to the high rate deterioration, the high rate deterioration evaluation value N at the time of the previous running is called from the memory of the control device 70.

Then, in step S12, the control device 70 determines whether or not a predetermined time has elapsed since the previous traveling. The predetermined time is sufficient time for the evaluation value N to return to 1. If the predetermined time has elapsed, the process proceeds to step S13, the evaluation value N = 1 at the start of traveling is acquired, and then the battery temperature (the average temperature of the plurality of battery cells 4 or the battery cell in which the high rate deterioration is most likely to occur) is likely to occur. The temperature of 4 (when there are a plurality of battery cells 4 arranged so that high rate deterioration is most likely to occur, the temperature of the battery cell 4 having the lowest temperature among the plurality of battery cells 4)) is detected (step S14).

On the other hand, if the predetermined time has not elapsed, the process proceeds to step S15, the current evaluation value N is acquired from the evaluation value N and the rest time map shown in FIG. 10, and then the process proceeds to step S14. The map shown in FIG. 10 shows the relationship between the ion bias evaluation value N as the high rate deterioration evaluation value and the rest time tr. For example, when the rest time tr is 1.2 hours, the ion bias evaluation value N is 0.7, and when the rest time is 8 hours, the evaluation value N is 0.97. According to FIG. 10, the “predetermined time” in step S12 corresponds to 11 hours, which is the rest time when the evaluation value N returns to 1.

Then, in step S16, it is determined whether or not the detected battery temperature has reached the target value. The target temperature is a relatively high temperature at which high rate deterioration is unlikely to occur, and a temperature suitable for the driver's operation is set.

When the battery temperature reaches the target temperature, the process proceeds to step S17, and the effective current of the battery 60 (that is, the entire plurality of battery cells 4) is detected. If the battery temperature has not reached the target temperature, the process proceeds to step S18, the battery temperature control is turned on, and then the process proceeds to step S17. In the battery temperature control, specifically, the temperature of the plurality of battery cells 4 is adjusted (heated or cooled) by the temperature control device to bring it closer to the target temperature (note that the target temperature does not have to be reached).

The following steps S19 to S25 basically perform the same operations as steps S2 to S7 in the basic control flowchart of FIG. 7, but the step of acquiring the limit integrated current value of step S20 from the map. The step of setting the upstream power supply value in step S24 and the step of limiting the effective current of S25 to the upper limit current value or less are different.

Specifically, the control device 70 (see FIG. 1) determines whether or not the effective current is larger than the threshold value (step S19).

If the effective current is larger than the threshold value, the process proceeds to step S20, the limit integrated current value is acquired from the map, and then the evaluation value N is calculated using the effective current value (step S21). On the other hand, if the effective current is smaller than the predetermined value, step S20 is skipped and the process proceeds to step S21.

Specifically, as for the method of obtaining the limit integrated current value in step S20, first, the effective current value (for example, 80A) is represented by a curve indicated by the three parameters of the effective current, the battery temperature, and the limit integrated amount in FIG. It is input to the map shown, and the integrated current value on the curve corresponding to the effective current value (40 to 95A) and the battery temperature T (° C.) is obtained as the limit integrated current value IS (Ah).

In step S21, the evaluation value N is obtained from the above (Equation 1) from the effective current value Ie (A), the elapsed time t (seconds), and the limit integrated current value IS (Ah) obtained in step S20.

Then, it is determined whether or not the evaluation value N is larger than the target value (step S22). The target value is an arbitrary numerical value, and is arbitrarily set in the range of 0 to 1, for example.

If the evaluation value N is larger than the target value, the process proceeds to step S23, the evaluation value N is recorded in the control device 70, and a series of current control is completed.

On the other hand, if the evaluation value N is smaller than the target value, the process proceeds to step S24, and the current setting unit 72 of the control device 70 sets an upper limit current value that brings the high rate deterioration evaluation value N closer to the target value (current setting step). Then, in step S25, the current control unit 73 limits the effective current to the upper limit current value or less (current control step). After that, the process proceeds to step S23 and ends.

By executing the above series of control flowcharts, the battery cell 4 that easily deteriorates at a high rate is specified in advance from the orientation of the battery cell 4 by the specifying unit 71 of the control device 70, and the specified battery cell 4 that easily deteriorates at a high rate is specified. It is possible to limit the effective current and suppress high rate deterioration.

As described above, as shown in FIG. 12, the plurality of battery cells 4 are controlled by controlling the current of the plurality of battery cells 4 based on the specified high rate deterioration evaluation value N of the battery cells 4 which are prone to high rate deterioration. When the effective current of the line Ie1 fluctuates with time, the high rate deterioration evaluation value N fluctuates like the line HE1. However, since the line HE1 does not fall below the threshold value S (for example, the evaluation value N = 0) at which high rate deterioration (high rate cycle bias deterioration) occurs, it can be seen that the high rate deterioration can be suppressed.

(Characteristics of this embodiment)
(1)
The control device 70 of the battery cell 4 of the first embodiment of the present invention controls the current of a plurality of battery cells 4 which are secondary batteries that can be charged and discharged but have different orientations. As shown in FIG. 1, the control device 70 has a specific unit 71 that identifies the battery cell 4 having the largest degree of transition from the orientation of each battery cell 4 to high rate deterioration, and the specified high rate of the battery cell 4. It includes a current setting unit 72 that sets an upper limit current value based on a state of transition to deterioration, and a current control unit 73 that limits the effective current value of the entire plurality of battery cells 4 to the upstream current value or less.

According to such a configuration, the specifying unit 71 identifies the cell having the largest degree of transition from the orientation of each battery cell 4 to the high rate deterioration from among the plurality of battery cells 4. Then, the current setting unit 72 sets the upper limit current value based on the transition state of the specified battery cell 4 to the high rate deterioration. The current control unit 73 limits the effective current value of the entire plurality of battery cells 4 to the upstream current value or less. As a result, in a configuration in which the currents of the plurality of battery cells 4 are controlled, it is possible to easily and surely suppress the transition of the battery cells 4 to high-rate deterioration without obtaining the currents and resistances of all the plurality of battery cells 4. become.

(2)
In the control device 70 of the battery cell 4 of the first embodiment, the battery cell 4 is interposed between the positive electrode sheet 6a, the negative electrode sheet 6b, and the positive electrode sheet 6a and the negative electrode sheet 6b, as shown in FIG. It is a configuration having a separator 6c impregnated with the electrolytic solution, and is specified when the direction in which the electrolytic solution is most likely to flow during charging / discharging of the battery cell 4 in the plane of the separator 6c is set to the first flow direction A1. Of the two battery cells 4 (for example, the battery cell 4A in FIG. 4A and the battery cell 4C in FIG. 4C), the unit 71 has a smaller angle between the first flow direction A1 and the vertical direction Z. The battery cell 4 is identified as the battery cell 4 (specifically, the battery cell 4C in FIG. 4C) having a large degree of transition to high-rate deterioration.

Of the two battery cells 4, the battery cell 4 having a small angle between the first flow direction A1 and the vertical direction Z, where the electrolytic solution is most likely to flow in the plane of the separator 6c during charging / discharging, is the electrolytic solution inside the battery cell 4. However, due to the influence of gravity, it tends to be biased in the first flow direction A1, and the ion concentration distribution between the poles (specifically, the lithium ion concentration distribution) is biased, so that high rate deterioration is likely to occur (that is, the transition to high rate deterioration). There is a tendency). Therefore, according to the above configuration, the specific unit 71 shifts the battery cell 4 having a small angle between the first flow direction A1 and the vertical direction Z to the high rate deterioration among the two battery cells 4. By specifying the battery cell 4, it becomes possible to reliably perform current control based on the battery cell 4, which tends to deteriorate at a high rate.

(3)
In the control device 70 of the battery cell 4 of the first embodiment, the battery cell 4 is interposed between the positive electrode sheet 6a, the negative electrode sheet 6b, and the positive electrode sheet 6a and the negative electrode sheet 6b, and is impregnated with the electrolytic solution. The configuration includes the separator 6c, and the direction in which the electrolytic solution is most likely to flow during charging / discharging of the battery cell 4 in the plane of the separator 6c is defined as the first flow direction A1, and the first in the plane of the separator 6c. When the direction orthogonal to the flow direction A1 is defined as the second flow direction A2, the identification unit 71 may use two battery cells 4 (for example, the battery cell 4A in FIG. 4A and the battery cell in FIG. 4B). Of 4B), the battery cell 4 having a small angle between the second flow direction A2 and the vertical direction Z has a large degree of transition to high-rate deterioration (specifically, the battery cell of FIG. 4A). 4A) is specified.

Of the two battery cells 4, the battery cell 4 having a small angle between the second flow direction A2 orthogonal to the first flow direction A1 in which the electrolytic solution easily flows and the vertical direction Z is the first in the plane of the separator 6c. 2 In the flow direction A2, the electrolytic solution tends to accumulate on the side closer to the downward direction, and the ion concentration distribution between the poles (specifically, the lithium ion concentration distribution) is biased, so that high-rate deterioration is likely to occur (that is, high-rate deterioration). The degree of transition is large). Therefore, according to the above configuration, the specific unit 71 shifts the battery cell 4 having a small angle between the second flow direction A2 and the vertical direction Z to the high rate deterioration among the two battery cells 4. By specifying the battery cell 4, it becomes possible to reliably perform current control based on the battery cell 4, which tends to deteriorate at a high rate.

(4)
The control method of the battery cell 4 of the first embodiment is a control method of the battery cell 4 that controls the current of the plurality of battery cells 4 which are the secondary batteries that can be charged and discharged and have different directions. Therefore, the upper limit current value is set based on the specific step of specifying the battery cell 4 having the largest degree of transition from the orientation of each battery cell 4 to high rate deterioration and the transition state of the specified battery cell 4 to high rate deterioration. It includes a current setting step for setting and a current control step for limiting the effective current value of the entire plurality of battery cells 4 to the upstream current value or less.

According to such a feature, in the specific step, the cell having the largest degree of transition from the orientation of each battery cell 4 to the high rate deterioration is specified from among the plurality of battery cells 4. Then, in the current setting step, the upper limit current value is set based on the transition state of the specified battery cell 4 to the high rate deterioration. Then, in the current control step, the effective current value of the entire plurality of battery cells 4 is limited to the upstream current value or less. As a result, when the current of the plurality of battery cells 4 is controlled, it is possible to easily and surely suppress the transition of the battery cells 4 to high rate deterioration without obtaining the current and resistance of all the plurality of battery cells 4. become.

(Second Embodiment)
The control device for the battery cell 4 according to the second embodiment of the present invention makes it possible to accelerate recovery from high-rate deterioration by weakening the binding force of the battery cell 4 while charging / discharging is paused.

If the pause time is not sufficient after charging / discharging the battery cell 4 with a large current (high rate), the battery cell 4 has not completely recovered from the high rate deterioration state, so only the current control of the first embodiment described above is performed. In this case, the effective current is easily limited, and it is difficult to improve the fuel efficiency and drive feel of the hybrid vehicle.

For example, the graph shown in FIG. 13 shows changes over time in the high rate deterioration evaluation value N (line HE2), effective current (line Ie2), and battery temperature (line T2). As shown by the line HE2, the high rate deterioration evaluation value N recovers only to N = 0.8 even when another 3 hours have passed after the rest time of 3 hours has elapsed, and is lower than N = 1. Therefore, the effective current of the battery cell 4 is limited.

In order to recover from high-rate deterioration when the pause time is not sufficient, the binding force of the battery cell 4 (that is, the distance between the plates during charging / discharging is shortened to reduce the internal resistance during the pause of the battery cell. It was found from the experiment that it is effective to temporarily weaken the pressing force between the plates to suppress it.

Specifically, when the battery cell 4 shown in FIG. 14 alternately repeats high-rate charging / discharging and hibernation, the case where the binding force of the dormant battery cell is small (P1) is larger (P2). ), It was found by experiment that the resistance increase rate Rθ (%) was smaller.

Therefore, in addition to the configuration of the control device 70 (see FIG. 1) of the first embodiment, the control device of the battery cell 4 of the second embodiment is shown in FIG. 15 (a) for early recovery from high rate deterioration. ), The restraint mechanism 22 shown in (b), specifically, the restraint mechanism 22 provided with the binding force applying unit 23 and the binding force control unit 24 is added.

The binding force applying unit 23 has a configuration in which a binding force is applied to the plurality of battery cells 4 in the compression direction. In FIGS. 15A and 15B, in a configuration in which a plurality of battery cells 4 are linearly arranged along a predetermined arrangement direction D, the binding force applying portion 23 is a battery of each from the predetermined arrangement direction D. It is configured to apply binding force to the cell 4 at the same time.

Specifically, the plurality of battery cells 4 are arranged horizontally in the thickness direction of the battery cells 4 and are housed in the casing 2 with the spring 13 interposed between the battery cells 4. The laminated body of the battery cell 4 is sandwiched by a pair of end plates 14 from both ends thereof. The binding force applying portion 23 rotates a pressing gear 15 that presses one end plate 14, a driving gear 17 that meshes with the pressing gear 15 and rotates so as to push the pressing gear 15 into the casing 2, and a drive gear 17. It includes a driving motor 16. As shown in FIGS. 15A and 15B, the binding force applying portion 23 pushes the pressing gear 15 into the casing 2 by the driving gear 17 receiving the driving force of the motor 16 to push the end plate 14 into the casing 2. A plurality of battery cells 4 arranged in the horizontal direction inside the casing 2 are laterally constrained and the spring 13 between the battery cells 4 is contracted.

Further, the configuration shown in FIGS. 15A and 15B further includes a bus bar 21 for connecting the battery cells 4. The bus bar 21 connects a pair of connection portions 21a electrically connected to the electrode terminals 19 of each battery cell 4 and a pair of connection portions 21a, and the plurality of battery cells 4 are connected from a predetermined arrangement direction D. It has an easily deformable portion 21b that deforms in a direction in which the length of the predetermined arrangement direction D changes when a binding force is applied. Since the bus bar 21 has the easily deformable portion 21b, it is possible to maintain the electrical connection between the battery cells 4 by the bus bar 21 even if the binding force to the battery cell 4 changes.

The binding force control unit 24 controls the motor 16 of the binding force applying unit 23 so as to weaken the binding force. When the deterioration evaluation value of the battery cell 4 having the highest degree of transition to high-rate deterioration is smaller than a predetermined value (for example, N <1), the binding force control unit 24 charges and discharges the plurality of battery cells 4. While resting, the binding force applying unit 23 is controlled so as to weaken the binding force on the battery cell 4 (that is, to return from the state of FIG. 15B to the state of FIG. 15A). ..

In the configuration in which the control device 70 (see FIG. 1) of the battery cell 4 further includes the binding force applying unit 23 and the binding force control unit 24 shown in FIGS. 15A and 15B as described above, the battery cell 4 is provided. The current control method of is executed according to the flowchart shown in FIG.

In the flowchart shown in FIG. 16, the operation is started by turning off the ignition of the hybrid vehicle (IG-OFF).

In step S31, the control device 70 (see FIG. 1) determines whether or not the worst high rate deterioration evaluation value N is smaller than 1 (N <1) immediately before IG-OFF. Here, the worst high-rate deterioration evaluation value N is the battery cell 4 (for example, in a state of being erected next to FIG. 4 (c)) in which the high-rate deterioration is most likely to be specified in advance by the specific unit 71 of the control device 70. It is a high rate deterioration evaluation value N at the time of traveling immediately before IG-OFF for the battery cell 4C).

If the high rate deterioration evaluation value N is smaller than 1, the process proceeds to step S32, and the binding force control unit 24 controls the binding force applying unit 23 to reduce the binding force of the battery cell 4. If the evaluation value N is 1 or more, the process proceeds to step S39, which will be described later, and then ends.

After the step of reducing the binding force of the battery cell 4 in step S32, the process proceeds to step S34, and the control device reads out a map of the high rate deterioration evaluation value and the rest time. Specifically, as shown in FIG. 17, it is a graph of the ion bias evaluation value N as a high rate deterioration evaluation value and the rest time tr (h), and the curve L1 having a small restraining force during rest and the rest. The graph showing the curve L2 having a large binding force is read out.

Then, in step S35, the high rate deterioration evaluation value is calculated from the rest time. Specifically, the ion bias evaluation value N as the high-rate deterioration evaluation value corresponding to the rest time is calculated from the curve L1 having a small restraining force during rest in the graph of FIG. Here, looking at the graph of FIG. 17, in the curve L1 in which the binding force during resting is small, the ion bias evaluation value N returns to 1 when the resting time t1 is 7 hours, whereas the binding force during resting is On the curve L2 with a large value, it can be seen that the ion bias evaluation value N does not return to 1 until the rest time t2 reaches 11 hours.

Then, in step S36, the control device determines whether or not the ignition is turned on (IG-ON). If IG-ON is not performed, the process proceeds to step S37, and if IG-ON is performed, the process proceeds to step S38.

In step S37, it is determined whether or not the high rate deterioration evaluation value N has reached 1 (N ≧ 1). If the evaluation value N has reached 1, the process proceeds to step S38, and if the evaluation value N has not reached 1, the process returns to step S35 and the evaluation value N is calculated again.

In step S38, the binding force control unit 24 controls the binding force applying unit 23 to return the binding force of the battery cell 4 to the state before the step of reducing the binding force in step S32.

Then, in step S39, the evaluation value N is recorded in the control device 70, and a series of control is completed.

As a result, by reducing the binding force of the battery cell 4 during the pause time, it becomes possible to recover from the high rate deterioration at an early stage.

By controlling the binding force of the battery cell 4 as described above, as shown in the graph of FIG. 18B, when there is a decrease in the binding force during hibernation as in the second embodiment (high rate deterioration evaluation). In the value N (line HE4), effective current (line Ie4), battery temperature (line T4)), when the high rate deterioration evaluation value N (line HE4) elapses for another 3 hours after the rest time of 3 hours elapses, It can be seen that N = 1 is restored and the high rate deterioration is restored early. On the other hand, as a comparative example, when there is no decrease in binding force during the rest period shown in FIG. 18A (high rate deterioration evaluation value N (line HE3), effective current (line Ie3), battery temperature (line T3), high rate deterioration Since the evaluation value N (line HE3) recovered only to N = 0.8 even when the rest time of 3 hours had passed and then 3 hours had passed, the evaluation value N (line HE3) was restored only to N = 0.8. It is clear that the decrease in binding force is effective for early recovery from high rate deterioration.

(Characteristics of the second embodiment)
(1)
In the control device for the battery cell 4 of the second embodiment of the present invention, the binding force applying unit 23 that applies a binding force to the plurality of battery cells 4 in the compression direction and the binding force applying unit 23 are subjected to the binding force. It is further provided with a binding force control unit 24 that controls the weakening.

In the binding force control unit 24, when the deterioration evaluation value indicating the state of transition to high rate deterioration in the battery cell 4 having the highest degree of transition to high rate deterioration is smaller than a predetermined value, the plurality of battery cells 4 are charged and discharged. The binding force applying unit 23 is controlled so as to weaken the binding force on the battery cell 4 while the battery cell 4 is paused.

The present inventors have experimentally found that if the binding force of the battery cells 4 is weakened while the plurality of battery cells 4 are inactive from charging / discharging, the recovery of the battery cells 4 from the high rate deterioration is accelerated. Therefore, according to the above configuration, while the plurality of battery cells 4 are inactive from charging / discharging, the binding force applying unit 23 weakens the binding force of the battery cells 4, so that the high rate deterioration of the battery cells 4 is caused. It will be possible to speed up the return.

(2)
The control device for the battery cells 4 of the second embodiment has a configuration in which a plurality of battery cells 4 are linearly arranged along a predetermined arrangement direction D, and the binding force applying unit 23 is each arranged from a predetermined arrangement direction D. A bus bar 21 that simultaneously applies a binding force to the battery cells 4 and connects the battery cells 4 to each other is further provided. The bus bar 21 has an easily deformable portion 21b that deforms in a direction in which the length of the predetermined arrangement direction D changes when the plurality of battery cells 4 receive a binding force from the predetermined arrangement direction D.

According to such a configuration, the bus bar 21 connecting the battery cells 4 has the easily deformable portion 21b, and the easily deformable portion 21b is the predetermined when the plurality of battery cells 4 are bound by the predetermined arrangement direction D. Deforms in the direction in which the length of the arrangement direction D of is changed. As a result, even if the distance between the battery cells 4 is deformed due to the change in the binding force applied to the battery cells 4, the electrical connection between the battery cells 4 can be easily maintained without a load.

4 Battery cell 6 Electrode winding body 6a Positive electrode sheet 6b Negative electrode sheet 6c Separator 21 Bus bar 21a Terminal connection 21b Easy deformation part 23 Binding force applying part 24 Binding force control part 60 Battery 70 Control device 71 Specific part 72 Current setting part 73 Current Control unit A1 1st flow direction A2 2nd flow direction D Arrangement direction

Claims (6)

A battery cell control device that controls the current of a plurality of battery cells that are rechargeable and dischargeable secondary batteries and have different orientations.
A specific part that identifies the battery cell with the highest degree of transition from the orientation of each battery cell to high rate deterioration, and
A current setting unit that sets an upper limit current value based on the specified transition state of the battery cell to high rate deterioration, and
A battery cell control device including a current control unit that limits the effective current value of the entire plurality of battery cells to the upstream current value or less. The battery cell has a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet and impregnated with an electrolytic solution.
When the direction in which the electrolytic solution is most likely to flow during charging / discharging of the battery cell in the plane of the separator is defined as the first flow direction,
Of the two battery cells, the specific unit identifies a battery cell having a small angle between the first flow direction and the vertical direction as a battery cell having a large degree of transition to high-rate deterioration.
The battery cell control device according to claim 1. The battery cell has a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet and impregnated with an electrolytic solution.
The direction in which the electrolytic solution is most likely to flow during charging and discharging of the battery cell in the plane of the separator is defined as the first flow direction, and the direction orthogonal to the first flow direction in the plane of the separator is the second. When defined as the flow direction
Of the two battery cells, the specific unit identifies a battery cell having a small angle between the second flow direction and the vertical direction as a battery cell having a large degree of transition to high-rate deterioration.
The battery cell control device according to claim 1 or 2. A binding force applying portion that applies a binding force to the plurality of battery cells in the compression direction,
Further provided with a binding force control unit for controlling the binding force applying unit,
When the deterioration evaluation value indicating the state of transition to high-rate deterioration in the battery cell having the highest degree of transition to high-rate deterioration is smaller than a predetermined value, the binding force control unit charges and discharges the plurality of battery cells. The binding force applying unit is controlled so as to weaken the binding force on the battery cell during the rest period.
The battery cell control device according to any one of claims 1 to 3. In a configuration in which the plurality of battery cells are linearly arranged along a predetermined arrangement direction, the plurality of battery cells are arranged linearly.
The binding force applying portion simultaneously applies a binding force to each of the battery cells from the predetermined arrangement direction.
It also has a bus bar that connects the battery cells.
The bus bar has an easily deformable portion that deforms in a direction in which the length in the predetermined arrangement direction changes when the plurality of battery cells receive a binding force from the predetermined arrangement direction.
The battery cell control device according to claim 4. It is a battery cell control method that controls the current of a plurality of battery cells that are rechargeable and dischargeable secondary batteries and have different orientations.
A specific step of identifying the battery cell having the highest degree of transition from the orientation of each battery cell to high rate deterioration, and
A current setting step of setting an upper limit current value based on the specified transition state of the battery cell to high rate deterioration, and
A method for controlling a battery cell, comprising a current control step of limiting the effective current value of the entire plurality of battery cells to the upstream current value or less.

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