WO2013005523A1

WO2013005523A1 - Assembled battery

Info

Publication number: WO2013005523A1
Application number: PCT/JP2012/064546
Authority: WO
Inventors: 小比賀　基治
Original assignee: 日産自動車株式会社
Priority date: 2011-07-04
Filing date: 2012-06-06
Publication date: 2013-01-10
Also published as: JP2013033723A

Abstract

An assembled battery (1) is provided with: a plurality of batteries (10, 20), which are laminated to each other; a heat insulating medium channel (31), which is provided between the batteries, and has a heat insulating medium circulating therein; and a cooling medium channel (32), which is provided between the batteries, and has a cooling medium circulating therein. The thermal resistance of the cooling medium is lower than that of the heat insulating medium. Heat transfer to the adjacent battery can be suppressed.

Description

Assembled battery

The present invention relates to an assembled battery.

In a battery pack in which a plurality of batteries are stacked, spacers having heat transfer portions on both sides of the heat insulating portion are inserted between the batteries, and the heat generated in the batteries is dissipated to the outside through the heat transfer portion of the spacer and the exterior member. An assembled battery is proposed (Patent Document 1).

However, the conventional technology has a problem that when a battery becomes hot, heat is transferred to an adjacent battery, and the adjacent battery is also heated.

JP 2010-218716 A

An object of the present invention is to provide an assembled battery that can suppress heat transfer to an adjacent battery.

In the present invention, a heat insulating medium passage through which the heat insulating medium flows and a refrigerant passage through which the refrigerant flows are provided between the plurality of stacked batteries, and the heat resistance of the refrigerant is made lower than the heat resistance of the heat insulating medium.

According to the present invention, by circulating the refrigerant and the heat insulating medium, the cooling effect of the refrigerant and the heat insulating effect of the heat insulating medium can be prevented from being lowered, and heat transfer to the adjacent battery can be suppressed.

It is a block diagram which shows the assembled battery which concerns on one embodiment of this invention. It is sectional drawing which shows the channel | path assembly plate of FIG. It is a flowchart which shows the control procedure of the flow control apparatus of FIG. It is a graph which shows the control mode of the heat insulation medium by FIG. It is a side view which shows the assembled battery which concerns on other embodiment of this invention.

As shown in FIG. 1, the assembled battery 1 is configured by laminating a plurality of

batteries

10 and 20, and a passage assembly plate 30 is interposed between the

batteries

10 and 20. The assembled battery 1 shown in the figure is a laminate of two

batteries

10 and 20, but may be a laminate of three or more batteries. In the assembled battery in which three or more batteries are stacked, the passage assembly plate 30 may be interposed between all the batteries, or a plurality of batteries may be interposed.

The configuration of one battery will be described by taking the battery 10 as an example (the battery 20 has the same configuration). In the battery 10, a power generation element is accommodated inside a pair of laminate film exterior members 11, and the pair of The outer peripheral part of the exterior member is sealed. In FIG. 1, only the exterior member 11 is shown, and the illustration of the power generation element is omitted. The laminated film constituting the exterior member 11 has, for example, a three-layer structure, and from the inner side to the outer side of the battery 10, for example, an electrolytic solution resistance and a heat fusion property such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. An inner resin layer composed of an excellent resin film, an intermediate metal layer composed of a metal foil such as aluminum, and a resin film excellent in electrical insulation such as a polyamide resin or a polyester resin And an outer resin layer.

As described above, in each of the pair of exterior members 11, for example, one surface (inner surface of the battery 10) of the intermediate metal layer made of aluminum foil or the like is made of a resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. It is made of a flexible material such as a resin-metal thin film laminate material obtained by laminating and laminating the other surface (the outer surface of the battery 10) with a polyamide resin or a polyester resin.

When the pair of exterior members 11 includes the intermediate metal layer in addition to the inner and outer resin layers, the strength of the exterior member 11 itself can be improved. Further, the inner resin layer of the exterior member 11 is made of, for example, a resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer, thereby ensuring good fusion with the

metal electrode terminals

12 and 13. It becomes possible to do.

In addition, the exterior member 11 in the present invention is not limited to the above-described three-layer structure, and may have a single-layer structure of the inner or outer resin layer. Moreover, the two-layer structure of either one of an inner side or an outer side resin layer, and an intermediate metal layer may be sufficient. Furthermore, the structure of four layers or more may be sufficient as needed.

Each of the pair of exterior members 11 has a shape in which a rectangular flat plate is formed into a shallow bowl shape (dish mold) so that the power generation element can be accommodated. And the entire circumference of the outer peripheral part is joined by heat fusion or an adhesive.

The battery 10 of this example is a lithium ion secondary battery, and the power generation element is configured by laminating a separator between a positive electrode plate and a negative electrode plate. The power generation element of this example can be composed of, for example, three positive plates, five separators, three negative plates, and an electrolyte. The battery 10 according to the present invention is not limited to a lithium ion secondary battery, and may be another battery.

The positive electrode plate constituting the power generation element includes a positive electrode side current collector extending to the positive electrode terminal 12 and positive electrode layers respectively formed on both main surfaces of part of the positive electrode side current collector. Note that the positive electrode plate and the positive electrode side current collector can be formed of a single conductor, or the positive electrode plate and the positive electrode side current collector can be formed of different members, and these can be joined.

The positive electrode side current collector of the positive electrode plate is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. The positive electrode layer of the positive electrode plate is made of, for example, lithium composite oxide such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or lithium cobaltate (LiCoO ₂ ), or a chalcogen (S, Se, Te) compound. A mixture of a positive electrode active material such as carbon black, a conductive agent such as carbon black, an adhesive such as an aqueous dispersion of polytetrafluoroethylene, and a solvent, is applied to both main surfaces of the positive electrode current collector plate, It is formed by drying and rolling.

The negative electrode plate constituting the power generation element includes a negative electrode side current collector extending to the negative electrode terminal 13 and negative electrode layers formed on both main surfaces of a part of the negative electrode side current collector. In addition, the negative electrode plate and the negative electrode side current collector can be formed of a single conductor, or the negative electrode plate and the negative electrode side current collector can be formed of different members and joined together.

The negative electrode side current collector of the negative electrode plate is made of an electrochemically stable metal foil such as nickel foil, copper foil, stainless steel foil, or iron foil. In addition, the negative electrode layer of the negative electrode plate is, for example, a negative electrode active material that occludes and releases lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. Mixing an aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body, and drying and then pulverizing, the carbon material surface carrying carbonized styrene butadiene rubber as the main material, This is formed by further mixing a binder such as an acrylic resin emulsion, applying the mixture to both main surfaces of the negative electrode current collector plate, drying and rolling.

The separator laminated between the positive electrode plate and the negative electrode plate prevents a short circuit between the positive electrode plate and the negative electrode plate, and may have a function of holding an electrolyte. This separator is a microporous film made of polyolefin such as polyethylene or polypropylene, for example. When an overcurrent flows, the separator also has a function of blocking the current by closing the pores of the layer due to heat generation. However, the separator is not limited to a single-layer film such as polyolefin, but a three-layer structure in which a polypropylene film is sandwiched between polyethylene films, or a laminate of a polyolefin microporous film and an organic nonwoven fabric can also be used. By forming the separator in multiple layers as described above, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (stiffness improvement) function can be provided.

The above power generation elements are formed by alternately stacking positive plates and negative plates through separators. The three positive plates are respectively connected to the positive terminal 12 made of metal foil via the positive current collector, while the three negative plates are similarly connected via the negative current collector. And a negative electrode terminal 13 made of metal foil.

As shown in FIG. 1, the positive electrode terminal 12 and the negative electrode terminal 13 are led out of the exterior member 11 from the positive electrode plate and the negative electrode plate of the power generation element. In the battery 10 of the present example, the positive electrode terminal 12 and the negative electrode terminal 13 are led out from the outer peripheral portion of the opposing sides (left and right sides in FIG. 1) of the exterior member 11. The positive terminal 12 and the negative terminal 13 are also referred to as a positive tab 12 and a negative tab 13.

The battery 10 is rectangular in plan view, but the outer shape of the battery 10 is not limited to a rectangle, and can be formed in a square or other polygons. Further, the lead-out positions of the positive electrode terminal 12 and the negative electrode terminal 13 may be led side by side from one outer peripheral portion in addition to being led from two opposing outer peripheral portions as in this example.

The battery 10 configured as described above can be used alone, but in this example, the battery 10 is connected to and combined with one or more other batteries 20 to be used as a secondary battery having a desired output and capacity. .

When the assembled battery 1 is configured by connecting a plurality of

batteries

10 and 20, the main surfaces of the plurality of

flat batteries

10 and 20 are stacked and accommodated in the battery case as shown in FIG. 1. Is called. In this case, the

positive terminals

12 and 22 and the

negative terminals

13 and 23 derived from the

batteries

10 and 20 are connected in series and / or in parallel using a bus bar.

Next, the passage assembly plate 30 interposed between the

batteries

10 and 20 will be described. The passage assembly plate 30 of this example is a plate-like member in which a heat insulating medium passage 31 through which a heat insulating medium flows and a refrigerant passage 32 through which a refrigerant flows are integrally formed.

The heat insulating medium is preferably a gas such as air or argon having a high thermal resistance, and the refrigerant is preferably a liquid such as ethylene glycol or silicon oil having a low thermal resistance. The heat resistance of the refrigerant is relatively lower than the heat resistance of the heat insulating medium. The heat insulating medium mainly functions to suppress transmission of relatively large temperature rise heat generated in the

battery

10 or 20 to the

adjacent battery

20 or 10, and the refrigerant is generated mainly when the

batteries

10 and 20 are charged / discharged. It functions to suppress a relatively gradual temperature rise.

A cross-sectional structure of the passage assembly plate 30 is shown in FIG. The passage assembly plate 30 of this example is made of a resin material having a high thermal resistance, for example, polypropylene, and is attached to the concave and

convex plates

33 and 34 having a honeycomb cross section and both the concave and

convex plates

33 and 34, respectively. And

thin plates

35 and 35 made of a metal material having a low thermal resistance, for example, aluminum. Then, the convex portions of the concavo-

convex plates

33 and 34 are overlapped and bonded as shown in FIG. 2, and the

thin plates

35 and 35 are attached to both surfaces thereof, so that the heat insulating medium passage 31 and the refrigerant passage 32 are hermetically sealed. The refrigerant passages 32 are formed so that the refrigerant passages 32 are located on both surfaces of the heat insulation medium passage 31 so as to be in a state. The passage assembly plate 30 is preferably extendable and contractible at least in the plane direction (two-dimensional direction). Further, since the heat insulating medium passage 31 and the refrigerant passage 32 are in contact with each other, the temperature rise of the heat insulating medium in the heat insulating medium passage 31 can be effectively suppressed by the refrigerant.

1, the refrigerant passage 32 on the upper surface of the passage assembly plate 30 is in contact with the lower main surface of the battery 10, and the refrigerant passage 32 on the lower surface is in contact with the upper main surface of the battery 20. Further, the heat insulating medium passage 31 of the passage assembly plate 30 shown in FIG. 1 is located between the

batteries

10 and 20. The passage assembly plate 30 is formed to have the same size or larger than the

exterior members

11 and 21 of the

batteries

10 and 20 in plan view. Therefore, a space exists between the

batteries

10 and 20 and the passage assembly plate 30 in the outer peripheral portion where the

exterior members

11 and 21 of the

batteries

10 and 20 are sealed.

As shown in FIG. 1, the refrigerant is stored in the refrigerant tank 36, sucked into the refrigerant circulation pipe 38 by the pump 37, circulated through the upper and lower

refrigerant passages

32, 32 of the passage assembly plate 30, and then returned to the refrigerant tank 36. . Although the cooling effect can be obtained even if the flow rate of the refrigerant passing through the refrigerant passage 32 is a constant amount, the flow rate control device 39 may further control the flow rate by outputting a control signal to the pump 37. For example, since the

batteries

10 and 20 generate heat gradually when charging and discharging, the refrigerant is circulated during charging and discharging, and the circulation of the refrigerant is stopped except during charging and discharging.

When the heat insulating medium is air, the surrounding air is sucked into the heat insulating medium circulation pipe 41 by the fan 40, and after flowing through the heat insulating medium passage 31 of the passage assembly plate 30, is released to the outside. In the case where the heat insulating medium is a gas such as argon gas, although not shown in the drawing, the air is sucked from the argon gas storage container to the heat insulating medium circulation pipe 41 by the fan 40 and circulated through the heat insulating medium passage 31 of the passage assembly plate 30. Return to gas storage container. Even if the flow rate of the heat insulating medium passing through the heat insulating medium passage 31 is a constant amount, the heat insulating effect can be obtained. However, the flow rate control device 39 may control the flow rate by outputting a control signal to the fan 40.

Each of the

batteries

10 and 20 is provided with

battery temperature sensors

42 and 43 for detecting the temperature of the

batteries

10 and 20, and the detection signals are output to the flow rate control device 39. In addition, an external temperature sensor 44 that detects the external temperature of the

batteries

10 and 20 is provided in the vicinity of the

batteries

10 and 20, and the detection signal is output to the flow control device 39. Note that the temperature of the heat insulating medium may be directly detected instead of the external temperature sensor 44.

Next, the control procedure of the flow rate of the heat insulating medium of the flow rate control device 39 will be described.
First, in step ST1, it is determined whether or not the battery temperatures of the

batteries

10 and 20 detected by the

battery temperature sensors

42 and 43 are equal to or higher than a _first predetermined temperature T1. The first predetermined temperature T ₁ is a temperature higher than the normal outside air temperature and is a limit temperature for protecting the

batteries

10 and 20.

When at least one of the battery temperatures of the

batteries

10 and 20 is equal to or higher than the _first predetermined temperature T _{1, the} process proceeds to step ST 2, the abnormal heat insulation medium circulation mode is set, and an operation command signal is sent from the flow controller 39 to the fan 40. The heat insulation medium is circulated through the heat insulation medium passage 31 of the passage assembly plate 30. If the heat insulation medium is not circulated, the heat insulation medium itself staying in the heat insulation medium passage 31 of the passage assembly plate 30 also becomes a high temperature, so that the effect of suppressing the transfer of the heat of the

battery

10 or 20 to the

adjacent battery

20 or 10 is small. Become. According to this example, since the heat insulating medium is circulated even when the

battery

10 or 20 becomes high temperature, it is possible to suppress the temperature rise of the heat insulating medium in the heat insulating medium passage 31 of the passage assembly plate 30, thereby transmitting to the adjacent battery. Heat can be suppressed.

When the battery temperature of the

batteries

10 and 20 is lower than the first predetermined temperature in step ST1, the process proceeds to step ST3. In step ST3, it is determined whether or not the external temperature detected by the external temperature sensor 44 is equal to or higher than a _second predetermined temperature T2. The second predetermined temperature T ₂ is lower than the first predetermined temperature T ₁ and is, for example, higher than the normal outside air temperature.

If the external temperature is equal to or higher than the _second predetermined temperature T2, the process proceeds to step ST5, the normal heat insulation medium circulation stop mode is set, a stop command signal is output from the flow control device 39 to the fan 40, and the passage assembly plate. The circulation of the heat insulation medium to the 30 heat insulation medium passages 31 is stopped. If the heat insulation medium is circulated through the heat insulation medium passage 31 when the external temperature is higher than the _second predetermined temperature T2, the heat insulation medium having a high temperature heats the refrigerant in the adjacent refrigerant passage 32. The cooling effect of the

batteries

10 and 20 by the refrigerant is reduced. According to this example, it is possible to prevent the cooling effect of such a refrigerant from being hindered.

If external temperature is a second lower than the predetermined temperature T _2, the process proceeds to step ST4, further external temperature determines whether a third predetermined temperature T ₃ below. The third predetermined temperature T ₃ is lower than the second predetermined temperature T ₂ and is, for example, a temperature close to or lower than the refrigerant temperature. When the external temperature is equal to or lower than the third predetermined temperature T ₃ , the process proceeds to step ST 6, the normal heat insulating medium circulation mode is set, an operation command signal is output from the flow control device 39 to the fan 40, and the passage assembly plate 30 The heat insulating medium is circulated through the heat insulating medium passage 31. When the external temperature is equal to or lower than the third predetermined temperature, the heat insulating medium is circulated through the heat insulating medium passage 31 of the passage assembly plate 30 so that the heat insulating medium can be used as the refrigerant in addition to the refrigerant.

If the external temperature exceeds a third predetermined temperature T ₃ at step ST4 proceeds to step ST5, sets the stop mode of the heat insulating medium circulating in the normal, the flow controller 39 to the fan 40 outputs a stop command signal Then, the circulation of the heat insulating medium to the heat insulating medium passage 31 of the passage assembly plate 30 is stopped. When the external temperature is between the second predetermined temperature and the third predetermined temperature, the cooling effect cannot be expected. On the contrary, the refrigerant in the adjacent refrigerant passage 32 is heated, and the cooling effect of the

batteries

10 and 20 by the refrigerant is increased. This is because it may decrease. FIG. 4 is a graph in which the vertical axis in FIG. 4 represents the battery temperature and the horizontal axis represents the external temperature, with the ranges of the abnormal heat insulation medium circulation mode, the normal insulation medium circulation stop mode, and the normal insulation medium circulation mode as described above. Is shown.

In the above-described embodiment, the

batteries

10 and 20 and the passage assembly plate 30 are simply stacked and not bonded, but one side of the passage assembly plate 30 is attached to the main body of the battery 10 as shown in FIG. The other surface may be bonded to the main surface of the battery 20. As described above, a gap due to sealing of the

batteries

10 and 20 exists between the outer periphery of the passage assembly plate 30 and the outer periphery of the

batteries

10 and 20, and the passage assembly plate 30 can be extended and contracted. Yes.

For this reason, when the

batteries

10 and 20 become hot and the

exterior members

11 and 21 expand, the passage assembly plate 30 is also stretched in the surface direction (two-dimensional direction) along with the expansion. Thereby, the heat insulation medium channel | path 31 of the channel | path assembly plate 30 expand | swells, and the heat insulation effect by a heat insulation medium improves.

As described above, according to the assembled battery 1 of the present example, the heat insulating medium passage 31 and the refrigerant passage 32 are provided between the

batteries

10 and 20 so that the heat resistance of the refrigerant is lower than the heat resistance of the heat insulating medium. Decrease in the cooling effect and the heat insulating effect of the heat insulating medium can be prevented, and heat transfer to adjacent batteries can be suppressed.

Further, since the refrigerant passage is provided between the battery and the heat insulating medium passage, it is possible to suppress the relatively large temperature rise heat generated in the battery 10 or the battery 20 from being transmitted to the adjacent battery 20 or the battery 10. In addition, for example, it is possible to suppress a relatively gradual temperature rise that occurs during charging / discharging of the

batteries

10 and 20, for example.

In addition, since the flow rate of the heat insulation medium is appropriately controlled according to the battery temperature and the external temperature, the heat insulation effect is sufficiently exhibited even when the temperature of the

batteries

10 and 20 rises abnormally without deteriorating the normal cooling performance by the refrigerant. can do.

Further, abnormality such as when the temperature of the

battery

10, 20 is a first predetermined temperature above T _1, since overwhelmingly higher than the battery temperature is outside the temperature, the heat insulating medium itself is stopped the flow of the heat insulating medium However, in this example, it is possible to prevent a decrease in the heat insulation effect and maintain a sufficient heat insulation effect by circulating the heat insulation medium.

Further, when the temperature of the

batteries

10 and 20 is lower than the first predetermined temperature T ₁ but is normal such that the temperature is equal to or higher than the second predetermined temperature T ₂ , when the heat insulating medium is circulated, for example, the external temperature is high. In some cases, the temperature of the heat insulating medium gradually increases, which may hinder cooling of the battery by the refrigerant. However, in this example, by stopping the circulation of the heat insulating medium, it can be prevented and a sufficient cooling effect can be maintained.

Further, when the temperature of the

batteries

10 and 20 is lower than the first predetermined temperature T ₁ and is normally lower than the third predetermined temperature T ₃ , the refrigerant is circulated by circulating the low-temperature heat insulating medium. In addition, it can be used as a cooling medium.

Further, if the

batteries

10 and 20 and the passage assembly plate 30 are bonded together, and the

exterior members

11 and 21 of the

batteries

10 and 20 expand in the event of an abnormality, the passage assembly plate 30 also moves in the plane direction (two-dimensional direction). To be stretched. Thereby, the heat insulation medium channel | path 31 of the channel | path assembly plate 30 expand | swells, and the heat insulation effect by a heat insulation medium improves.

The

battery temperature sensors

42 and 43 correspond to the battery temperature detection means according to the present invention, the external temperature sensor 44 corresponds to the external temperature detection means according to the present invention, and the flow rate control device 39 corresponds to the flow rate control according to the present invention. Corresponds to means.

Claims

A plurality of stacked batteries;
A heat insulating medium passage provided between the batteries and through which the heat insulating medium flows;
A refrigerant passage provided between the batteries and through which the refrigerant flows;
With
The battery pack has a thermal resistance lower than that of the heat insulating medium.
The assembled battery according to claim 1, wherein the refrigerant passage is provided between the battery and the heat insulating medium passage.
Battery temperature detecting means for detecting the temperature of the battery;
An external temperature detecting means for detecting an external temperature of the battery;
Flow rate control means for controlling the flow rate of the heat insulating medium flowing through the heat insulating medium passage;
Further comprising
The assembled battery according to claim 1, wherein the flow rate control unit controls the flow rate of the heat insulating medium flowing through the heat insulating medium passage according to the temperature of the battery and the external temperature.
The assembled battery according to claim 3, wherein the flow rate control means causes the heat insulating medium to flow through the heat insulating medium passage when the temperature of the battery is equal to or higher than a first predetermined temperature.
The flow rate control means stops the flow of the heat insulating medium in the heat insulating medium passage when the temperature of the battery is lower than the first predetermined temperature and the external temperature is equal to or higher than a second predetermined temperature. The assembled battery described in 1.
The flow rate control means causes the heat insulating medium to flow through the heat insulating medium passage when the temperature of the battery is lower than the first predetermined temperature and the external temperature is equal to or lower than a third predetermined temperature. The assembled battery described in 1.
A passage assembly plate in which the heat insulating medium passage and the refrigerant passage are integrally formed;
The assembled battery according to any one of claims 1 to 6, wherein the passage assembly plate is bonded to a main surface of the battery.