JP2010040345A - Battery system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a battery system capable of sufficiently dissipating heat of a battery, achieving life prolongation by uniformizing a constituent pressure applied to each single battery, and furthermore, improving reliability by suppressing an internal short circuit due to deformation of the single battery. <P>SOLUTION: The battery system includes: pressurizing cooling means 4, each of which is composed of two pressurizing plates 2 to pressurize each single battery 1 and cooling conduits 3 which are positioned between these pressurizing plates 2, and deformed by a pressure while allowing a coolant to pass inside thereof; a pressure sensor 30 arranged between the pressurizing plate 2 and the single battery 1; a memory 32 which stores upper and lower limit reference values; a control part 31 which compares an input signal from the pressure sensor 30 with both limit reference values of the memory 32, and outputs a pump driving control signal when a comparison result is not within a reference range; and a pump drive part 33 which changes a transportation amount of the coolant per unit time in a pump 34 in accordance with the pump driving control signal from the control part 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery system including an assembled battery having a structure in which a plurality of plate-shaped single cells are arranged between two restraint plates held at a fixed distance so as to be substantially flat with the restraint plate. .

  For example, a power source for power mounted on a robot, an electric vehicle, or the like is hermetically sealed in a limited space, so that it is desired to be small and light and low cost. In recent years, lithium ion batteries having a high energy density have attracted attention as satisfying such demands. In order to obtain a high output, this lithium ion battery is used as a battery system by connecting a large number of batteries, for example, about 5 or 6 cells to about 10 or more cells in series or in parallel. In addition, space saving is required even when a stationary type is used as a backup application for a wireless base station or the like.

  Here, when charging and discharging the lithium ion battery, the battery temperature may rise. At this time, if the assembled battery is configured with the side surfaces of the batteries being in close contact with each other, the heat dissipation of the battery is reduced. There is a problem that the battery temperature rises further due to insufficiency, and as a result, the life of the assembled battery decreases.

  In addition, in a lithium ion battery, the phenomenon that the electrode expands during charging and the electrode contracts during discharging is remarkable, so that the surface pressure may increase abnormally locally between adjacent unit cells. For this reason, there has been a problem that the cell is greatly deformed and the electrodes are crushed to cause an internal short circuit.

  Further, in the lithium ion battery, when the distance between the electrode plates increases, the electron conductivity in the positive electrode active material layer and the negative electrode active material layer decreases, so that the internal resistance of the battery increases and the battery capacity decreases. The cycle characteristics may be deteriorated. In particular, in a single cell using a flexible outer package such as an aluminum laminate, it is difficult to apply the battery constituent pressure, and thus there is a problem that the distance between the electrode plates increases and the above-mentioned disadvantages are remarkably generated.

In view of the above, the following inventions have been proposed.
(1) An assembled battery in which a plurality of unit cells are stacked includes a holding member for stacking while holding the unit cells fixed, and the holding member allows a cooling fluid to flow between the stacked unit cells. Constructed invention (see Patent Document 1 below).

(2) An assembled battery to be cooled, a box in which the assembled battery is housed and filled with a cooling liquid, a circulation path for deriving the cooling liquid from the box and introducing the cooling liquid into the box, and a circulation path An invention that includes a pump that circulates the coolant in the circulation passage and a radiator that is provided in the circulation passage and cools the coolant in the circulation passage (see Patent Document 2 below).

(3) An invention in which a surface pressure diffusing member is interposed between single cells (see Patent Document 3 below).
(4) A surface pressure buffering mechanism interposed between each of the power storage cells is provided, and the surface pressure buffering mechanism includes a flat plate and a cushion plate stacked in the stacking direction of the power storage cells, and responds to the surface pressure. The invention in which the cushion plate is deformed to absorb the surface pressure (see Patent Document 4 below).

JP 2002-319383 A JP 2003-346924 A JP 2006-196230 A JP 2007-165698 A

However, the above-described invention has the following problems.
The subject of the invention of (1) The pressurization of the pressurizing member is a structure that pressurizes each unit cell by tightening two constraining plates provided at both ends of the assembled battery with a connecting rod. In this case, it is necessary to increase the tightening force by the connecting rod, and as a result, the restraint plate bends (specifically, the distance between the restraint plates near the connecting rod is separated from the connecting rod). Bend to be shorter than the distance between the constraining plates at the part). For this reason, a sufficient component pressure can be applied to a portion close to the connecting rod (periphery of the unit cell), but a sufficient component pressure can be applied to a portion away from the connecting rod (the central portion of the unit cell). I can't. As a result, there has been a problem that the internal resistance of the unit cell increases, leading to a decrease in battery capacity and a decrease in cycle characteristics.

Problem of invention of (2) Since the assembled battery which becomes a core is accommodated in the box, the box becomes very large. Therefore, the entire cooling structure of the battery system is increased in size. Moreover, when it is going to apply a component pressure to the assembled battery in a box with a cooling fluid, since it will be necessary to circulate a lot of refrigerant | coolants, a pump will also be enlarged. For these reasons, the manufacturing cost of the battery system increases.

Problem of invention of (3) If it is the structure which interposes a surface pressure diffusion member between single cells, the structural pressure added to a single cell will be determined by the elastic force of a surface pressure diffusion member, and a structural pressure may be adjusted. Can not. Specifically, when the unit cell expands, the surface pressure diffusion member contracts greatly, so that the component pressure applied to the unit cell increases, whereas when the unit cell contracts, the surface pressure diffusion member does not contract so much. The component pressure applied to the unit cell is reduced. For this reason, when the unit cell expands, the component pressure applied to the unit cell increases, and as a result, the electrode may be squeezed to cause an internal short circuit, and when the unit cell contracts, the unit cell is applied to the unit cell. As a result of the reduced pressure, there is a problem that the life of the assembled battery is reduced.

Problem of invention of (4) If it is the structure where a flat plate and a cushion board exist between single cells, the constituent pressure added to a single battery will be determined with the elastic force of a cushion board, and a constituent pressure cannot be adjusted. Therefore, there is a problem similar to the problem of the invention of (3) above.

  The present invention can sufficiently dissipate the heat of the battery, and can achieve a long life by making the constituent pressure applied to each unit cell uniform, and also prevents an internal short circuit caused by the deformation of the unit cell. It aims at providing the battery system which can improve reliability by suppressing at low cost.

  In order to achieve the above object, the present invention includes two restraint plates held at a fixed distance, and a plate-like unit cell disposed between the restraint plates so as to be substantially flat with the restraint plates. A pressure cooling means disposed between the unit cells, and the pressure cooling unit is disposed in contact with the unit cells and pressurizes each unit cell, and An assembled battery composed of a cooling conduit that is positioned between these pressure plates and that allows the refrigerant to pass therethrough and that can be deformed by pressure, a pump that sends the refrigerant to the cooling conduit, the pressure plate, and the unit cell A pressure detection means arranged between, a storage means storing a lower limit reference value that is a minimum allowable pressure by the pressure plate, an input signal from the pressure detection means, and a lower limit reference value of the storage means The input signal is below the lower reference value. In this case, a control means for outputting a pump drive control signal and a pump drive means for increasing the refrigerant transport amount per unit time in the pump according to the pump drive control signal from the control means are provided. Features.

  If it has a pressure plate arranged so as to be in contact with each unit cell as in the above configuration, and a cooling conduit that is located between the pressure plates and through which the refrigerant passes, the heat generated from the unit cell is Since it is transmitted to the cooling pipe through the pressure plate, it is absorbed by the refrigerant passing through the inside of the cooling pipe. Therefore, the heat dissipation of the battery can be sufficiently performed, so that the life of the assembled battery can be extended.

  In addition, pressure cooling means composed of two pressure plates and cooling pipes are arranged between the plurality of single cells, respectively, and each single cell is pressurized by the pressure cooling means. As a result, it is possible to solve the shortage of the component pressure at the center of the unit cell due to the bending of the restraint plate. Therefore, it can suppress that the internal resistance of a single cell rises and a battery capacity fall and a cycle characteristic fall arise.

Further, the control means compares the input signal from the pressure detection means with the lower limit reference value of the storage means, and if it falls below the lower limit reference value (when the unit cell contracts greatly), the pump drive control signal is pumped. It outputs to a drive means, and, thereby, the refrigerant transport amount per unit time in a pump increases. In this case, since the cooling pipe is configured to be deformable, when the refrigerant transport amount per unit time in the pump increases (that is, when the internal pressure by the refrigerant increases), the cooling pipe is accordingly increased. Deforms in the direction of swelling.
As described above, when the unit cell is greatly contracted, the cooling conduit is deformed in the direction of swelling, so that the component pressure applied to each unit cell can be suppressed from being significantly reduced or non-uniform, and as a result, The life of the assembled battery can be extended.

  In addition, since it is only necessary to circulate the refrigerant in the cooling pipe, it is not necessary to circulate a large amount of refrigerant. Therefore, since the battery pack cooling structure and the pump can be downsized, the manufacturing cost of the battery system is reduced.

The storage means stores an upper limit reference value that is the maximum allowable pressure by the pressure plate, and the control means compares the input signal from the pressure detection means with the upper limit reference value of the storage means. When the input signal exceeds the upper limit reference value, a pump drive control signal is output, and the pump drive means can reduce the refrigerant transport amount per unit time in the pump in response to the pump drive control signal. desirable.
With the above configuration, the control means compares the input signal from the pressure detection means with the upper limit reference value of the storage means, and if the upper limit reference value is exceeded (when the unit cell is greatly expanded), the pump drive control signal is This is output to the pump driving means, whereby the refrigerant transport amount per unit time in the pump is reduced (that is, the internal pressure by the refrigerant is reduced). Therefore, since the cooling conduit is deformed in the direction of withering, it is possible to suppress the deformation of the unit cell and the occurrence of an internal short circuit caused by applying a large component pressure to the unit cell.

The unit cell is preferably a prismatic lithium ion battery.
This is because the lithium ion battery has a larger amount of expansion / contraction during charging / discharging than a nickel-hydrogen battery and the like, and thus the effects of the present invention are sufficiently exhibited.

It is desirable that the cooling conduits of the pressure cooling means are divided into two or more.
If the cooling pipeline of each pressurized cooling means is divided into two or more (if there are two or more refrigerant inflow portions in the cooling pipeline of each pressurized cooling means), fresh refrigerant (relative Since the contact area between the pressure plate (unit cell) and the pressure plate (single cell) becomes large, the cooling effect of the battery is further exhibited. In addition, by applying pressure to the pressure plate from multiple locations with the same pressure, the component pressure becomes more uniform within the surface to be pressurized of each unit cell, so it is possible to suppress a decrease in battery capacity and a decrease in cycle characteristics. it can.

It is desirable that all the cooling pipes of the pressure cooling means are configured to communicate with each other.
If all the cooling pipelines of the pressure cooling means are in communication, the component pressure applied to the unit cell is made uniform, so that it is possible to further suppress the decrease in battery capacity and the decrease in cycle characteristics.

It is desirable that the refrigerant inflow side in the cooling conduit is located at the center of the unit cell.
In the unit cell, the center part is more likely to generate heat than the end part, so it is preferable to cool the center part more intensively than the end part, but the refrigerant inflow side in the cooling conduit is located in the center part of the unit cell. In this case, since the fresh refrigerant (refrigerant having a relatively low temperature) controls the cooling function of the central portion of the unit cell, the central portion is preferentially cooled from the end portion.

A concave portion slightly larger than the unit cell is formed on the surface of the pressure plate on the unit cell side, and it is desirable that a part of the unit cell is fitted in the recess.
If a part of the unit cell is fitted in the recess formed in the pressure plate, the thickness of the assembled cell is reduced by that amount, so that the size of the assembled cell can be reduced, and the contact between the pressure plate and the unit cell is reduced. Since the area increases, the cooling function of the unit cell is further exhibited.

Desirably, the surface of the cooling pipe line in the pressure plate is provided with a cooling pipe guide protrusion that contacts a part of the cooling pipe line along the arrangement position of the cooling pipe line. .
If the surface of the cooling pipe line on the pressure plate is provided with a cooling pipe guide projection that contacts a part of the cooling pipe along the position of the cooling pipe, the cooling pipe Since it is only necessary to dispose the cooling pipeline along the projection for guiding the pipeline, manufacturing of the assembled battery can be facilitated. In addition, since a part of the cooling pipe line and the cooling pipe guide projection are in contact with each other, the contact area between the pressure plate and the cooling pipe line is increased, and the cooling function of the unit cell is further exhibited. It will be. If the cooling pipe guide projection has a shape that follows the outer peripheral surface of the cooling pipe, and the cooling pipe guide protrusion is fitted into the cooling pipe guide projection, The said effect is further exhibited.

  According to the present invention, it is possible to sufficiently dissipate the battery and make the constituent pressure applied to each unit cell uniform, so that it is possible to extend the life of the assembled battery and to deform the unit cell. As a result, the reliability of the assembled battery can be improved, and a battery system having such an assembled battery can be provided at low cost.

  Hereinafter, a battery system according to the present invention will be described with reference to FIGS. In addition, the battery system in this invention is not limited to what was shown to the following form, In the range which does not change the summary, it can implement suitably.

  As shown in FIGS. 1-4, the assembled battery 50 used for the battery system of this invention is arrange | positioned between the single cell (lithium secondary battery) 1 and the single cell 1, and pressurizes each single cell 1 2 An assembled battery body comprising the pressure plate 2 and the pressure cooling means 4 comprising the substantially cylindrical cooling conduit 3 positioned between the pressure plates 2, and the unit cell 1 and the pressure cooling means 4. 2 side bases (restraint plates) 6 that restrain 5 at both ends of the assembled battery main body 5, a connecting bar 7 that connects the side bases 6, negative electrode current collector leads 9 and positive electrode current collector leads 10 described later. And a terminal connection block 8 for electrically connecting each other.

  As shown in FIG. 5, the unit cell 1 has a welded portion 1 a in which aluminum laminate films 1 c are welded to each other on the outer peripheral portion. From the welded portion 1 a, the positive electrode current collector lead 10 and ultrasonic welding are provided. The cathode current collecting tab 12 welded by a method or the like, the anode current collecting lead 9 and the anode current collecting tab 13 welded by an ultrasonic welding method or the like protrude. In addition, a non-aqueous electrolyte and a laminated electrode body 17 are accommodated in a storage space (not shown) formed by two convex portions 1b provided at the center of the laminate film 1c. As shown in FIG. 6, the body 17 has a structure in which a large number of negative separators 15 and bag-like separators 16 containing positive electrodes 14 are stacked, and the negative electrode 15 is disposed at the outermost position. Since the negative electrode 15 is arranged at the outermost position as described above, the number of the negative electrodes 15 is one more than the number of the positive electrodes 14 (specifically, the number of the positive electrodes 14 is 50). The negative electrode 15 is composed of 51 sheets).

The positive electrode 14 has a structure in which a positive electrode active material layer containing a positive electrode active material made of LiCoO ₂ is formed on both surfaces of a positive electrode core made of aluminum foil, and the negative electrode 15 is made of a negative electrode core made of copper foil. In this structure, a negative electrode active material layer containing a negative electrode active material made of carbon is formed on both sides.
The unit cell 1 has a nominal capacity of 12 Ah, and the dimensions are a width L1 of 100 mm, a height L2 of 110 mm, and a thickness L3 of 15 mm.

  The pressure plate 2 is made of aluminum, and as shown in FIG. 7, the height L4 is 115 mm, the width L5 is 106 mm, and the depth L6 is 4 mm. Further, on one surface of the pressure plate 2, as shown in FIGS. 7 to 9, a cooling pipe guide protrusion 2a (height) along the outer peripheral surface of the substantially cylindrical cooling pipe 3 is provided. L8 is 1.2 mm and width L9 is 4 mm). If the cooling pipe guide projection 2a is provided in this way, the cooling pipe 3 may be disposed along the cooling pipe guide projection 2a, and thus the battery pack 50 can be easily manufactured. In addition, since a part of the cooling pipe 3 and the cooling pipe guide projection 2a are in contact with each other, the contact area between the pressure plate 2 and the cooling pipe 3 is increased. The cooling function of the single cell 1 is sufficiently exhibited.

  On the other hand, a concave portion 2b (depth L7 is 2 mm) slightly larger than the convex portion 1b of the single cell 1 is formed on the other surface of the pressure plate 2, and the convex portion 1b of the single cell 1 is formed in the concave portion 2b. It is inserted. With such a configuration, the thickness of the assembled battery 50 can be reduced, so that the assembled battery 50 can be reduced in size and the contact area between the pressure plate 2 and the single battery 1 is increased. The cooling function 1 is sufficiently exhibited.

  The cooling conduit 3 has a diameter of about 4 mm in a fully expanded state, and is configured such that a refrigerant (water in this embodiment) passes through the inside thereof. Further, the cooling pipe 3 has a structure in which a tube made of polyurethane elastomer is covered with polyester fiber. By covering the tube with polyester fiber in this way, the pressure resistance of the cooling pipe 3 is improved and the internal pressure is increased. As a result, the diameter of the cooling pipe 3 is prevented from expanding beyond a predetermined value (4 mm).

  Further, at the time of assembling the battery system, the cooling conduit 3 has a slightly deflated shape as shown in FIG. 11, but after the battery system is assembled, an internal pressure is applied to the cooling conduit 3 through the refrigerant. In this case, as shown in FIG. 10, it is configured to swell and form a substantially circular shape (however, it is not in a fully expanded state, but can be further expanded when the flow rate of the refrigerant increases. Is). With this configuration, the repulsive force due to the cooling conduit 3 can be reduced when the assembled battery 50 is assembled, so that the battery system can be easily manufactured and after the battery system is assembled. By swelling, the pressure plate 2 (unit cell 1) can be sufficiently pressurized. The distance L12 between the pressure plates 2 when assembling the battery system is about 3 mm. When the cooling conduit 3 is inflated after assembly, the distance L11 between the pressure plates 2 is about 3.8 mm. ing. In addition, a large number of cooling pipes 3 are branched from one thick main pipe (not shown), and this main pipe has a cooler (heat exchange) that re-cools the refrigerant heated by the heat of the battery. And a pump to be described later.

  The two side bases 6 are made of PEEK (polyetheretherketone), and a plurality of recesses 6a are formed on the outer surface in order to improve heat dissipation and reduce weight. The connecting bar 7 is made of stainless steel and is fixed to the side base 6 with bolts 20. Further, the terminal connection block 8 is made of stainless steel, and the negative electrode current collecting leads 9 or the positive electrode current collecting leads 10 are fixed with bolts 21.

  Here, as shown in FIGS. 3 and 12, a pressure sensor (pressure detecting means) 30 is provided between the unit cell 1 and the pressure plate 2. As shown in FIG. 12, in addition to the assembled battery 50 and the pressure sensor 30, the battery system includes a control unit (control unit) 31, a memory (storage unit) 32, and a pump drive unit (pump drive unit). ) 33 and a pump (compressor) 34.

  The memory 32 has an upper limit reference value (M1, specifically 0.4 Pa) that is the maximum allowable pressure by the pressure plate 2, and a lower limit reference value (M2) that is the minimum allowable pressure by the pressure plate 2. , Specifically 0.2 MPa). Further, the control unit 31 compares the value (P) of the input signal from the pressure sensor 30 with both reference values of the memory 32, and if it is not within the reference range (the value of the pressure sensor 30 is the upper limit reference). When the value exceeds the value, or when the value of the pressure sensor 30 is below the lower limit reference value), a pump drive control signal is output.

  Further, the pump drive unit 33 changes the refrigerant transport amount per unit time in the pump 34 according to the pump drive control signal from the control unit 31. The pump 34 supplies refrigerant to the cooling pipe 3 and initially pressurizes the refrigerant to 1 MPa (in this case, the pressure applied to the unit cell 1 is 0.3 MPa). .

The operation of the battery system having the above configuration will be described below with reference to FIG.
First, when the power is turned on, the controller 31 determines whether or not the value (P) of the input signal from the pressure sensor 30 is larger than the upper reference value (M1) at a predetermined interval (step S1). If it is true, a pump drive control signal is output to the pump drive unit 33, and the pressure of the refrigerant in the pump 34 is reduced (that is, the refrigerant supply amount per unit time is reduced) (step S2). As a result, as shown in FIG. 10, the cooling conduit 3 that has been inflated becomes deflated as shown in FIG. 11, so that the pressure applied to the unit cell 1 from the pressure plate 2 decreases. . Therefore, it is possible to suppress the deformation of the battery and the internal short circuit of the battery due to the large pressure applied to the single cell 1.

  On the other hand, if the determination in step S1 is negative, the control unit 31 determines whether or not the value (P) of the input signal from the pressure sensor 30 is smaller than the lower limit reference value (M2) (step S3). If it is true, a pump drive control signal is output to the pump drive unit 33 to increase the pressure of the refrigerant in the pump 34 (that is, increase the amount of refrigerant supplied per unit time) (step S4). As a result, as shown in FIG. 11, the cooling conduit 3 that has been in a deflated state becomes inflated as shown in FIG. 10, so that the pressure applied to the unit cell 1 from the pressure plate 2 increases. . Accordingly, it is possible to suppress a decrease in battery capacity and a decrease in cycle characteristics due to the pressure applied to the unit cell 1 being too small. On the other hand, if the determination in step S3 is negative, the above-described operation is repeated.

  Thus, when the cell 1 is greatly expanded (when the value (P) of the input signal from the pressure sensor 30 is larger than the upper limit reference value (M1)), the cooling conduit 3 is deformed in a deflated direction. Therefore, the deformation of the unit cell 1 is suppressed, and as a result, the occurrence of an internal short circuit can be suppressed. On the other hand, when the single cell is greatly contracted (when the value (P) of the input signal from the pressure sensor 30 is smaller than the lower limit reference value (M2)), the cooling conduit 3 is deformed in the expanding direction. It can suppress that the component pressure added to the cell 1 falls or becomes non-uniform | heterogenous, As a result, lifetime improvement of the assembled battery 50 can be achieved.

(Example)
As the battery of the example, the same battery system as described in the best mode for carrying out the invention was used.
Hereinafter, such a battery system is referred to as a battery system A of the present invention.

(Comparative example)
As shown in FIG. 14, in the same manner as in the above embodiment, except that a simple pressure plate 40 made of stainless steel is used instead of the pressure cooling means 4 and a stainless steel plate is used as the side surface base (restraint plate) 6. An assembled battery was produced.
Hereinafter, the assembled battery having such a structure is referred to as a comparative battery Z.

(Experiment)
In the battery system A and the comparative battery Z of the present invention, a pressure-sensitive paper (a portion where a pressure of 0.2 MPa or more is applied is discolored) is disposed between the pressure plate 2 and the single cell 1, and the pressure distribution applied to both cells. FIG. 15 shows the result of the comparative battery Z, and FIG. 16 shows the result of the battery system A of the present invention (in these figures, the discolored portion is indicated by hatching). The measurement in the battery system A and the comparative battery Z of the present invention was performed by disposing the pressure sensitive paper after disposing the pressure sensitive paper at the time of production of each battery system or battery, and observing it.

As is clear from FIGS. 15 and 16, in the battery system A of the present invention, a sufficient component pressure is obtained at any part, whereas in the comparative battery Z, the end of the unit cell is sufficient. Although a constituent pressure was obtained, it was confirmed that a sufficient constituent pressure could not be obtained at the center of the unit cell.
This is because, in the comparative battery Z, the side surface base 6 bends (specifically, the distance between the side surface bases 6 in the region close to the connecting rod 7 is larger than the distance between the side surface bases 6 in the region away from the connecting rod 7 Therefore, a sufficient component pressure cannot be obtained at the central portion of the unit cell 1. On the other hand, in the battery system A of the present invention, each unit cell 1 is pressurized by a pressure cooling means 4 provided between the unit cells 1 and comprising a pressurizing plate 2 and a cooling conduit 3. Therefore, it is considered that the shortage of the component pressure at the central portion of the unit cell 1 due to the bending of the side surface base 6 can be solved.

(Other matters)
(1) In the above embodiment, the cooling pipes 3 used for one pressure cooling means 4 are configured separately (specifically, in the above embodiment, one pressure cooling means 4 includes 9 However, the present invention is not limited to such a configuration. As shown in FIG. 17, the cooling pipeline 3 used for one pressure cooling means 4 is integrated. You may comprise. With such a configuration, the number of branches from the main pipeline decreases (specifically, in the above embodiment, the number of cooling pipelines 3 branched from the main pipeline is only five), so the assembled battery 50 can be easily manufactured. In FIG. 17, 3a is a refrigerant inflow side, and 3b is a refrigerant outflow side. This is the same in the drawings described later.

  Further, instead of integrally forming the cooling pipe 3, it may be divided into two as shown in FIG. 18. At this time, if the refrigerant inflow side 3a is arranged on the center side of the unit cell 1, fresh refrigerant (low temperature refrigerant) is supplied to the center of the unit cell 1 where heat is easily generated. It becomes possible to suppress the temperature rise in the part.

Furthermore, in order to suppress the temperature rise in the central portion of the unit cell 1, a cooling conduit 3 having a shape as shown in FIG. 19 may be used.
In addition, the number of main pipelines is not limited to one, and two or more main pipelines may be provided. In this case, it is necessary to provide a cooler and a pump in each main pipeline.

(2) When it is necessary to further suppress the temperature rise of the unit cell 1, as shown in FIG. 20, in addition to the cooling pipe 3 disposed between the pressure plates 2, The cooling conduit 41 may be formed separately.

(3) The refrigerant is not limited to the above water, but may be oil, ammonia or the like. In this case, when water is used as the refrigerant, a cooler (heat exchanger) is not necessarily required. However, when oil, ammonia, or the like is used as the refrigerant, a cooler is required.

(4) The cooling conduit is not limited to a two-layer tube, but may be a one-layer tube made of polyurethane or the like, or a three-layer tube.

(5) In the above embodiment, not only the lower limit reference value but also the upper limit reference value is stored in the memory, but the upper limit reference value does not necessarily have to be stored in the memory.
(6) The single battery is not limited to the lithium secondary battery, but may be a nickel-hydrogen secondary battery or the like.

  The present invention can be applied to a power source for power mounted on, for example, a robot or an electric vehicle.

It is a perspective view of the assembled battery used for the battery system of this invention. It is a perspective view of the assembled battery used for the battery system of this invention, Comprising: It is a figure except a connection bar. It is a partial exploded perspective view of the assembled battery used for the battery system of this invention. It is typical sectional drawing of the assembled battery used for the battery system of this invention. It is a perspective view of the single cell used for the battery system of this invention. It is a disassembled perspective view of a laminated electrode body. It is a perspective view of a pressure plate used for the battery system of the present invention. It is an exploded view of a pressure plate and a cooling pipe used in the battery system of the present invention. It is the figure which expanded the A section of FIG. It is explanatory drawing which shows the state which the pipe for cooling expanded. It is explanatory drawing which shows the state which the cooling pipe line deflated. It is a block diagram which shows the structure of the battery system of this invention. It is a flowchart which shows the operation state in the battery system of this invention. It is a perspective view of the assembled battery of a comparative example. 4 is an explanatory diagram showing a state of pressure-sensitive paper in a comparative battery Z. FIG. It is explanatory drawing which shows the state of the pressure sensitive paper in this invention battery system. It is a perspective view which shows the modification of the pipe line for cooling. It is a perspective view which shows the other modification of the pipe line for cooling. It is a perspective view which shows the further another modification of the pipe line for cooling. It is a perspective view which shows the modification of a pressurization board.

Explanation of symbols

1: Cell 2: Pressurizing plate 2a: Cooling pipe guide protrusion 2b: Recess 3: Cooling pipe 6: Side base (restraint plate)
30: Pressure sensor (pressure detection means)
31: Control unit (control means)
32: Memory (memory means)
33: Pump drive unit (pump drive means)
34: Pump 50: Battery pack

Claims (8)

Two constraining plates held at a fixed distance, a plurality of plate-shaped cells arranged between the constraining plates so as to be substantially flat with the constraining plates, and pressure cooling disposed between these single cells The pressure cooling means is arranged so as to be in contact with each unit cell and pressurizes each unit cell. An assembled battery composed of a cooling conduit that passes and can be deformed by pressure;
A pump for sending the refrigerant to the cooling pipe;
Pressure detecting means disposed between the pressure plate and the unit cell;
Storage means for storing a lower limit reference value which is a minimum allowable pressure by the pressure plate;
A control means for comparing the input signal from the pressure detection means with the lower limit reference value of the storage means, and outputting a pump drive control signal when the input signal falls below the lower limit reference value;
Pump drive means for increasing the refrigerant transport amount per unit time in the pump in response to a pump drive control signal from the control means;
A battery system comprising:   The storage means stores an upper limit reference value that is the maximum allowable pressure by the pressure plate, and the control means compares the input signal from the pressure detection means with the upper limit reference value of the storage means. When the input signal exceeds the upper limit reference value, a pump drive control signal is output, and the pump drive means decreases the refrigerant transport amount per unit time in the pump in response to the pump drive control signal. Item 4. The battery system according to Item 1.   The battery system according to claim 1 or 2, wherein the unit cell is a prismatic lithium ion battery.   4. The battery system according to any one of 1 to 3, wherein a cooling pipeline of each of the pressure cooling means is divided into two or more.   The battery system according to any one of claims 1 to 4, wherein all of the cooling pipelines of the pressure cooling means are configured to communicate with each other.   The battery system according to any one of claims 1 to 5, wherein a refrigerant inflow side in the cooling conduit is located at a central portion of the unit cell.   The surface on the unit cell side of the pressure plate is formed with a recess that is slightly larger than the unit cell, and a part of the unit cell is fitted in the recess. The battery system described.   The surface of the pressure plate on the cooling pipe side is provided with a cooling pipe guide protrusion that contacts a part of the cooling pipe along the position of the cooling pipe. The battery system according to any one of 1 to 7.

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