JP3899423B2 - Thin battery module - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a thin battery module configured by combining a plurality of thin secondary batteries, and more particularly to a thin battery module to which a battery control board for monitoring and controlling the battery module can be mounted.
[0002]
[Background]
A battery module in which a plurality of secondary batteries (cells) are combined is provided with a battery control board (cell controller) for monitoring and controlling the battery modules such as voltage detection, temperature detection or control of each secondary battery. . The battery control board is attached to a position such as an upper part of a housing that houses the battery module in a state of being housed in a case configured separately, and between each secondary battery and the battery control board, the cell A voltage detection line, a battery temperature detection line, and a control line are wired (see, for example, Japanese Patent Laid-Open No. 10-246112).
[0003]
However, the conventional battery module as described above has a problem that the number of wirings around the battery module increases as the number of cells increases, so that the manufacturing work becomes much troublesome.
[0004]
DISCLOSURE OF THE INVENTION
An object of the present invention is to simplify cell monitoring or control wiring.
[0005]
According to the present invention, a plurality of thin batteries in which a positive electrode terminal and a negative electrode terminal are led out from opposite edges of the outer peripheral portion of the battery exterior are arranged side by side, and one of the positive terminals of each of the thin batteries and the same polarity terminal of the negative electrode terminal. A thin battery module in which a plurality of subassemblies consisting of a thin battery and a pair of busbars are stacked in series and electrically connected in series, and the subassemblies are stacked. 2, two bus bar fitting contacts that are electrically connected to each other so that ends of two bus bars adjacent to each other in the stacking direction of the subassembly can be fitted in parallel, and the two bus bar fitting contacts are electrically connected to each other. A plurality of connectors each having a board-fitting contact that can be fitted to a connection part of a battery control board that controls the thin battery. An end portion of the bus bar and an end portion of the bus bar of another subassembly adjacent to the stacking direction are fitted to the bus bar fitting contact of the connector so that the plurality of subassemblies are electrically connected in series. In addition, a thin battery module is provided in which the connection portion of the battery control board is fitted to the board fitting contacts of the plurality of connectors.
[0006]
In the present invention, a bus bar that is modularized by connecting a thin battery is used for cell monitoring or control wiring. That is, the end of the bus bar in which a plurality of thin batteries are connected in parallel is fitted to the bus bar fitting contact of the connector, and the connection part of the battery control board is fitted to the board fitting contact, so that the voltage of this part The temperature can be detected or this part can be controlled. This eliminates the need for wiring to be provided separately, so that even if the number of cells is increased, there is no wiring around the battery module, and the manufacturing workability is remarkably improved.
[0007]
In the present invention, the bus bars of adjacent subassemblies are fitted to the bus bar fitting contacts of the connector, so that these subassemblies are connected in series. Thereby, it is not necessary to use a complicated shape for connecting the bus bars, the bus bar can have a simple shape such as a flat plate shape, and parts can be shared, space saving, and cost reduction can be achieved.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0009]
First, a thin battery according to an embodiment of the present invention will be described with reference to FIG. FIG. 10A is a plan view showing the entire thin battery according to the embodiment of the present invention, and FIG. 10B is a cross-sectional view taken along line BB in FIG. FIG. 10 shows one thin battery (also referred to as a unit battery or a cell), and a battery module 1 (also referred to as an assembled battery) having a desired voltage and capacity is configured by combining a plurality of the thin batteries 10.
[0010]
The thin battery 10 of this example is a lithium-based thin secondary battery, and includes two positive plates 101, five separators 102, two negative plates 103, a positive terminal 104, a negative terminal 105, It is comprised from the upper battery exterior 106, the lower battery exterior 107, and the electrolyte which is not shown in particular. Among these, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 109.
[0011]
The number of positive plates 101, separators 102, and negative plates 103 is not limited in any way, and the power generation element 109 can be configured with one positive plate 101, three separators 102, and one negative plate 104. . The number of positive electrode plates, negative electrode plates, and separators can be selected and configured as necessary.
[0012]
The positive electrode plate 101 that constitutes the power generation element 109 includes, for example, 100 weight ratio of a positive electrode active material such as a metal oxide, a conductive material such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene. : A mixture of 3:10 is applied to both surfaces of a metal foil such as an aluminum foil as a positive electrode side current collector, dried, rolled, and then cut into a predetermined size. In addition, the mixing ratio of said aqueous dispersion of polytetrafluoroethylene is the solid content.
[0013]
Examples of the positive electrode active material include lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), lithium cobaltate (LiCoO ₂ ), and chalcogen (S, Se, Te) compounds. Can do.
[0014]
The negative electrode plate 103 constituting the power generation element 109 is made of 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. An aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body is mixed at a solid content ratio of, for example, 100: 5, dried and then pulverized to support carbonized styrene butadiene rubber on the surface of carbon particles The resulting material is mixed with a binder such as an acrylic resin emulsion at a weight ratio of, for example, 100: 5, and this mixture is used as a metal foil such as nickel foil or copper foil as a negative electrode side current collector. These are coated on both sides, dried, rolled, and then cut into a predetermined size.
[0015]
In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. However, when used as a power source for an electric vehicle or the like, it is advantageous because there is no sudden drop in output.
[0016]
In addition, the separator 102 of the power generation element 109 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 described above, and may have a function of holding an electrolyte. The separator 102 is a microporous film having a thickness of 25 μm to 50 μm made of, for example, polyolefin such as polyethylene (PE) or polypropylene (PP). Has a function of blocking the current.
[0017]
The separator 102 according to the present invention is not limited to a single-layer film such as polyolefin, but a three-layer structure in which a polypropylene layer is sandwiched between polyethylene layers, or a laminate of a polyolefin microporous film and an organic nonwoven fabric may be used. it can. By forming the separator 102 in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided. Further, instead of the separator 102, a gel electrolyte or an intrinsic polymer electrolyte can be used.
[0018]
The above power generation elements 109 are laminated in such an order that the positive electrode plates 101 and the negative electrode plates 103 are alternately arranged from above and the separators 102 are positioned between the positive electrode plates 101 and the negative electrode plates 102. The separators 102 are stacked one by one on the top and bottom. Each of the two positive plates 101 is connected to the positive terminal 104 made of metal foil via the positive current collector 104a, while the two negative plates 103 are connected to the negative current collector 105a. Is connected to the negative electrode terminal 105 which is also made of metal foil. The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include aluminum and an aluminum alloy, and examples of the negative electrode terminal 105 include nickel and copper. Or stainless steel. In addition, both the positive electrode side current collector 104a and the negative electrode side current collector 105a in this example are configured by extending the aluminum foil, nickel foil, and copper foil that constitute the current collector of the positive electrode plate 104 and the negative electrode plate 105. However, the current collectors 104a and 105a can be formed of separate materials and parts.
[0019]
The power generation element 109 is sealed by the upper battery casing 106 and the lower battery casing 107. The upper battery casing 106 and the lower battery casing 107 are flexible, such as a resin film of polyethylene or polypropylene, a resin-metal thin film laminate material in which both surfaces of a metal foil such as aluminum are laminated with a resin such as polyethylene or polypropylene, and the like. It is formed with the material which has. In particular, the resin film constituting the inner surfaces of the battery outer casings 106 and 107 is made of, for example, polyethylene, polypropylene, ionomer resin, etc. having excellent chemical resistance to the electrolyte and excellent heat sealability of the outer periphery, and in the middle. For example, a resin film constituting the outer surface of the battery exterior 106, 107 is interposed between a metal foil excellent in flexibility and strength, such as aluminum foil and stainless steel foil, for example, a polyamide resin or a polyester resin excellent in electrical insulation. Or the like.
[0020]
The upper battery casing 106 and the lower battery casing 107 enclose the power generation element 109, the positive current collector 104a, a part of the positive terminal 104, the negative current collector 105a, and a part of the negative terminal 105. After injecting a liquid electrolyte having a lithium salt such as lithium perchlorate and lithium borofluoride into the organic liquid solvent into the space formed by the battery casings 106 and 107, the upper battery casing 106 and the lower battery casing 107 The outer peripheral edge is sealed by a method such as heat fusion.
[0021]
Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC), but the organic liquid solvent of the present invention is not limited thereto, An organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) and dietoshikiethane (DEE) in an ester solvent can also be used.
[0022]
As shown in the figure, the positive terminal 104 is led out from one end of the sealed battery casings 106 and 107, but the upper battery casing 106 and the lower battery casing 107 have a thickness corresponding to the thickness of the positive terminal 104. In order to maintain the sealing performance in the thin battery 10, a seal film made of polyethylene or polypropylene is applied to the portion where the positive electrode terminal 104 and the battery exterior 106, 107 are in contact with each other. It can also be interposed by a method such as heat fusion.
[0023]
Similarly, the negative electrode terminal 105 is led out from the other end of the sealed battery casings 106 and 107, and here, similarly to the positive terminal 104 side, the negative electrode terminal 105 and the battery casings 106 and 107 It is also possible to interpose a seal film at the portion where the contacts. In any of the positive electrode terminal 104 and the negative electrode terminal 105, it is desirable from the viewpoint of heat-sealability that the seal film is made of a resin of the same system as the resin constituting the battery casings 106 and 107.
[0024]
The external appearance of the above thin battery 10 is shown in FIGS. In the present embodiment, the thin battery 10 is connected as shown in the equivalent circuit diagram of FIG. 1 to form the battery module 1, and a specific structure thereof will be described with reference to FIGS.
[0025]
First, as shown in FIG. 5, four thin batteries 10 are connected in parallel, and are set as subassemblies 1a, 1b,. That is, the positive terminals 104 of the four thin batteries 10 are connected to one bus bar 20 and the negative terminals 105 are connected to the other bus bar 22. The connection between the positive electrode terminal 104 and the bus bar 20 and the connection between the negative electrode terminal 105 and the bus bar 22 are not limited as long as they are electrically connected, but can be performed by, for example, welding.
[0026]
Here, each of the bus bar 20 and the bus bar 22 has a flat plate shape having the same shape, and is made of a conductive material such as copper, nickel, and stainless steel. When four thin batteries 10 are juxtaposed, four positive electrodes are provided. The length is such that the terminal 104 and the negative electrode terminal 105 can be connected. The bus bars 20 and 22 in this example have the same shape, but are denoted by different reference numerals 20 and 22 in order to identify the bus bar connected to the positive terminal 104 and the bus bar connected to the negative terminal 105 of the thin battery 10. I will do it.
[0027]
The 11 subassemblies 1a, 1b,..., 1k configured by connecting the bus bar 20 and the bus bar 22 in parallel to the positive terminal 104 and the negative terminal 105 of the four thin batteries 10 are stacked as shown in FIG. At this time, the subassemblies 1a, 1b,..., 1k are stacked so that they are sequentially connected in series. That is, the subassembly 1a and the next-stage subassembly 1b are stacked such that the positive electrode terminal 104 and the negative electrode terminal 105 are reversed (rotated 180 ° in a plane). Similarly, the positive electrode terminal 104 and the negative electrode terminal 105 are laminated so as to be reversed even in the subassembly 1b and the subassembly 1c in the next stage.
[0028]
In the present embodiment, the subassemblies 1a, 1b,..., 1k stacked in 11 stages are connected in series using the connector 50. The connector 50 of this example is shown in FIGS. The connector 50 has a main body 51 made of, for example, a conductive material such as copper, nickel, and stainless steel, and has two groove-shaped bus bar fitting contacts in which the two bus bars 20 and 22 can be fitted in parallel. 52 and 52 and a groove-like board fitting contact 53 which is provided at a right angle to which the edge of the battery control board 40 can be fitted. Each of the bus bar fitting contact 52 and the board fitting contact 53 is provided with an elastic body that sandwiches the edges of the bus bars 20 and 22 and the battery control board 40, and thereby the bus bars 20 and 22 and the battery control board 40. Can be held only by fitting them to the bus bar fitting contact 52 or the board fitting contact 53.
[0029]
Further, since the main body 51 of the connector 50 is made of a conductive material, the two bus bar fitting contacts 52, 52 and these and the board fitting contact 53 are electrically connected. In addition, the main body 51 of the connector 50 is made of an insulator such as plastic, and a conductive member is inserted therein, thereby electrically connecting the bus bar fitting contacts 52, 52 to each other and the board fitting contact 53. May be.
[0030]
The connector 50 is fixed to the inner wall of the housing 30 that houses the battery module 1 as shown in FIG. A means for fixing the connector 50 to the inner wall of the housing 30 is not particularly limited. For example, when the plastic housing 30 is molded, the connector 50 can be fixed by inserting. Although only two opposing surfaces 30a and 30b of the housing 30 are shown in the figure, six connectors 50 are fixed to the inner walls of the two housing surfaces 30a and 30b.
[0031]
The bus bar fitting contacts 52 and 52 of the connector 50 are fitted to the bus bars 20 and 22 of adjacent subassemblies so that the 11 subassemblies 1a, 1b... 1k are connected in series as a whole. Twelve connectors 50 are arranged for convenience by six.
[0032]
This configuration will be described more specifically with reference to FIG. In the figure, 12 connectors are identified as 50a, 50b,.
[0033]
First, the positive bus bar 20 of the uppermost subassembly 1a is connected to a positive terminal 31 for a load such as a motor or a generator, and is connected to a connector 50a provided on the uppermost stage of the housing surface 30b on the front side. However, the positive-side bus bar 20 of the subassembly 1a does not need to be connected in series with the negative-side bus bar 22 of the adjacent sub-assembly 1b, so that it is simply connected to one of the two bus bar fitting contacts 52 of the connector 50. It is only necessary to make it fit.
[0034]
The negative bus bar 22 of the same subassembly 1a is fitted to the bus bar fitting contact 52 on the upper side of the connector 50b provided on the uppermost stage of the housing surface 30a. Then, in order to connect the uppermost subassembly 1a and the next-stage subassembly 1b in series, the positive busbar 20 of the next-stage subassembly 1b is fitted to the busbar fitting contact 52 on the lower side of the connector 50b. .
[0035]
Further, the negative bus bar 22 of the subassembly 1b is fitted to the bus bar fitting contact 52 on the upper side of the connector 50c provided on the second stage of the housing surface 30b on the front side of the figure, and the subassembly 1b and the next stage are connected to the subassembly 1b. In order to connect the sub-assembly 1c in series, the positive bus bar 20 of the next-stage sub-assembly 1c is fitted to the bus-bar fitting contact 52 on the lower side of the connector 50c. Similarly, the eleven sub-assemblies 1a, 1b,..., 1k positive bus bar 20 and negative electrode bus bar 22 are fitted into the twelve bus bar fitting contacts 52, 52 of twelve connectors 50a, 50b,.
[0036]
FIG. 8 is a view taken along the line VIII of FIG. 5, FIG. 9 is a view taken along the line IX, and FIG. The negative electrode bus bar 22 of the lowermost subassembly 1k is connected to the negative electrode terminal 32 for a load such as a motor or a generator, and is not connected to the adjacent upper subassembly 1j, so the positive electrode of the uppermost subassembly 1a. Similar to the bus bar 20, it is only necessary to fit the bus bar fitting contact 52 of the connector 50l.
[0037]
In the battery module 1 in which 11 subassemblies 1a, 1b,..., 1k are stacked and connected in series as described above, the bus bars 20 and 22 used for connecting the four thin batteries 10 in parallel and the connector 50 are connected to the voltage. Shared for detection lines. That is, when the stacked battery modules 1 shown in FIG. 5 are accommodated in the housing 30, twelve convenient connectors 50a, 50b,..., 50l fixed to the housing surfaces 30a, 30b facing each other. The battery control board 40 is fitted to the board fitting contact 53. At this time, six connection portions (contact points) 41 are formed at both ends of the battery control board 40, and the connection portions 41 and the board fitting contacts 53 are electrically connected.
[0038]
The battery control board 40 has a predetermined pattern formed on an insulating board, and is mounted with a microcomputer 43 for detecting the voltage of the battery module 1 and executing control. In this example, six and twelve connection portions 41 are formed on each side edge of the insulating substrate, and each connection portion 41 is electrically connected to a predetermined terminal of the microcomputer 43. Patterned.
[0039]
Incidentally, in order to detect each voltage of the eleven subassemblies 1a, 1b,... Composed of four thin batteries 10, from the positive terminal 104 of the eleven subassemblies, as shown in the equivalent circuit diagram of FIG. Voltage signal and a voltage signal from the negative terminal of the subassembly 1k located at the end are required.
[0040]
Further, in the battery module 1 configured to be stacked as shown in FIG. 5, the bus bar 20 that connects the positive terminal 104 of the uppermost subassembly 1a and the negative terminal 105 of the lowermost subassembly 1k are connected. Since the bus bar 22 is connected to a load such as a motor or a generator, when the battery module 1 is housed in the housing 30, the two positive terminals and the negative terminal are respectively connected to the outside of the housing 30. Connect to exposed terminals 31 and 32. In the figure, only the positive electrode side 31 is shown, and the negative electrode side terminal 32 is provided below the opposite surface of the housing surface 30a. In FIG. 5, the housing surfaces other than the housing surfaces 30a and 30b are omitted.
[0041]
As described above, in the battery module 1 according to the present embodiment, when the voltages of the subassemblies 1a, 1b,..., 1k are detected, the battery control is performed via the connector 50 without using the bus bars 20 and 22. Since it is configured to be connected to the connection portion 41 of the substrate 40, the conventional signal wiring is not required, and the operation of signal wiring and the layout of the signal wiring are remarkably simplified. Such an effect becomes more prominent as the number of batteries 10 constituting the battery module 1 increases.
[0042]
In addition, when conventional signal wiring is used, there is a problem in the accuracy of the detection signal because the signal voltage drops or varies due to non-uniformity or variation in the length of the signal wiring or contact loss at the connection portion. In the battery module of this embodiment, the bus bars 20 and 22 are uniform in length, and the number of connecting portions is one, so that the accuracy of the detection signal is remarkably improved.
[0043]
Furthermore, in the conventional type, the voltage detection wiring that sends a relatively high voltage detection signal affects the temperature detection line and control line that sends the low voltage signal, and this has an adverse effect on the temperature detection signal and control signal. However, in the battery module 1 of the present embodiment, the bus bars 20 and 22 themselves are used as the voltage detection lines, so that the influence is eliminated.
[0044]
In addition, when the battery module 1 is mounted on a vehicle, additional parts and the like are required for countermeasures against interference and disconnection due to vibration during traveling, but in the battery module 1 of the present embodiment, the bus bars 20 and 22 are used as voltage detection lines. These measures are unnecessary because they are used.
[0045]
Further, in the present embodiment, the connectors 50a, 50b,... 50l are used to connect the subassemblies 1a, 1b,..., 1k in series with each other. It can be as simple as As a result, space saving and cost reduction by sharing parts can be achieved.
[0046]
The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[0047]
In the above-described embodiment, the bus bars 20 and 22 are used for voltage detection. However, the bus bars 20 and 22 can also be used for battery temperature detection and battery control.
[Brief description of the drawings]
FIG. 1 is an equivalent circuit diagram showing a battery module according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a thin battery according to an embodiment of the present invention.
FIG. 3 is a side view showing a thin battery according to an embodiment of the present invention.
FIG. 4 is a schematic diagram showing a battery module according to an embodiment of the present invention.
FIG. 5 is a partially exploded perspective view showing a battery module according to an embodiment of the present invention.
FIG. 6 is a perspective view showing a connector according to an embodiment of the present invention.
FIG. 7 is a three-side view showing the connector according to the embodiment of the present invention.
8 is a view taken along arrow VIII in FIG.
FIG. 9 is a view taken along arrow IX in FIG. 5;
10A is a plan view showing the entire thin battery according to the embodiment of the present invention, and FIG. 10B is a sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery module 1a, 1b ..., 1k ... Subassembly 10 ... Thin battery 101 ... Positive electrode plate 102 ... Separator 103 ... Negative electrode plate 104 ... Positive electrode terminal 104a ... Positive electrode side current collection part 105 ... Negative electrode terminal 106 ... Upper battery exterior 107 ... Lower battery exterior 109 ... Power generation element 20 ... Positive electrode side bus bar 22 ... Negative electrode side bus bar 30 ... Case 40 ... Battery control board 41 ... Connector 43 ... Microcomputer 50 ... Connector 51 ... Body 52 ... Bus bar fitting contact 53 ... Fitting board Joint

Claims (6)

A plurality of thin batteries, in which a positive electrode terminal and a negative electrode terminal are led out from opposite edges of the outer periphery of the battery exterior, are arranged in parallel, and one of the same polar terminals of each of the thin batteries is connected by a pair of bus bars. A thin battery module that is electrically connected in parallel, and in which a plurality of subassemblies consisting of these thin batteries and bus bar pairs are stacked and electrically connected in series,
In the state where the subassemblies are stacked, two electrically connected busbar fitting contacts that can be fitted in parallel at the ends of two busbars adjacent in the stacking direction of the subassemblies, A plurality of connectors that are electrically connected to one bus bar fitting contact and have a board fitting contact that can be fitted to a connection portion of a battery control board that controls the thin battery;
An end of the bus bar of one subassembly and an end of the bus bar of another subassembly adjacent thereto in the stacking direction are fitted to the busbar fitting contact of the connector so that the plurality of subassemblies are electrically connected. The battery module is connected in series, and the battery control board connection portion is fitted to the board fitting contacts of the plurality of connectors. The thin battery module according to claim 1, wherein the bus bar fitting contact and the board fitting contact of the connector are each formed in a groove shape into which the bus bar can be fitted, and are provided substantially at right angles to each other. The thin battery module according to claim 1, wherein the battery control board is provided on a surface along a stacking direction of the sub-assemblies. The thin battery module according to claim 1, wherein a plurality of the subassemblies are stacked and accommodated in a housing, and the connector is provided on an inner wall of the housing. The thin battery module according to any one of claims 1 to 4, wherein the connection part of the battery control board constitutes means for detecting a potential of a bus bar connected to the connection part. The thin battery module according to claim 1, wherein the bus bar is formed in a flat plate shape.

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