KR20100006491U - Temperature Sensor for Battery Pack - Google Patents

Abstract

The present invention is a temperature sensor for measuring the temperature of the battery cell in the battery pack structure of a plurality of battery cells to make an electrical connection and built in the pack case, the temperature sensor is a flexible thin rectangular shape for precise temperature measurement It is made of a structure and provides a temperature sensor, characterized in that the adhesive layer for adhesion with the battery cell is formed on one surface so as to be attached to the outer surface of the battery cell.

In the present invention, the temperature sensor is formed on one surface of the adhesive layer for adhesion with the battery cell so that the temperature sensor can be attached to the outer surface of the battery cell for precise temperature measurement. Since the process time can be shortened, the productivity can be improved.

Description

Temperature Sensor for Battery Pack {Temperature Sensor for Battery Pack}

The present invention relates to a temperature sensor for a battery pack, and more particularly, a temperature sensor for measuring the temperature of the battery cell in a battery pack having a structure in which a plurality of battery cells make an electrical connection and built in the pack case, the temperature The sensor is made of a flexible thin rectangular structure for precise temperature measurement, and an adhesive layer for adhesion to the battery cell is formed on one surface to be attached to the outer surface of the battery cell. will be.

The present invention also relates to a battery pack characterized in that the temperature sensor according to the present invention is connected to a control unit for controlling the operation of the battery pack.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and accordingly, a lot of researches on secondary batteries that can meet various needs have been conducted.

Secondary batteries are classified into cylindrical secondary batteries, rectangular secondary batteries, and pouch type secondary batteries according to their shapes. In terms of materials, secondary batteries may be used for lithium secondary batteries such as lithium ion batteries having high energy density, discharge voltage, output stability, and lithium ion polymer batteries. The demand is high.

Secondary batteries are repeatedly charged and discharged during the operation, and in this process, a large amount of heat may be generated and the output voltage state of the battery may be changed. The increase in temperature and the change in the output voltage due to the heat generation not only cause malfunction of the device using the battery and reduce operating efficiency, but also cause a shortening of the battery life.

In addition, since the battery pack has a plurality of battery cells are built in the pack case, when some battery cells are overvoltage, overcurrent, overheating, the safety and operation efficiency of the battery pack is a big problem, so a means for detecting them is necessary. Therefore, the temperature sensor is connected to the battery cells to check and control the operation state in real time or at regular intervals.

However, the conventional mounting or connection of the temperature sensor has been cumbersome to mount or connect the temperature sensor using a separate adhesive or a member for fixing. This makes the assembly process of the battery pack very complicated, which is a barrier to improving productivity.

1 and 2 illustrate a battery cell to which a temperature sensor is attached using an existing method.

Referring to FIG. 1, a pack case 10 includes a plurality of battery cells 20, and a temperature sensor 30 for detecting a temperature of a battery is attached to an outer surface of the battery cell 20. The temperature sensor 30 is a thermistor and an adhesive glue is used to fix the temperature sensor 30 to the outer surface of the battery cell 20.

Referring to FIG. 2, the temperature sensor 30 attached to the outer surface of the battery cell 20 is fixed by the tape 40.

As described above, the existing temperature sensor has to go through the process of applying the adhesive to the area to which the temperature sensor is to be attached in advance and attaching and fixing the tape on the attached temperature sensor, making the assembly process of the battery pack very complicated and productive. There was a problem dropping.

Therefore, there is a need for mounting means of a temperature sensor to shorten the process and improve productivity.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

After extensive research and various experiments, the inventors of the present application have made a flexible thin rectangular structure of the temperature sensor for measuring the temperature of the battery cell in the battery pack, and adhered to the battery cell for precise temperature measurement. By forming the adhesive layer for one surface, it was confirmed that the above problems can be solved and came to complete the present invention.

Therefore, the temperature sensor according to the present invention, as a temperature sensor for measuring the temperature of the battery cell in the battery pack structure of the plurality of battery cells to form an electrical connection and is built in the pack case, the temperature sensor is a precise temperature measurement To this end, it is made of a flexible thin rectangular structure and is configured to be formed on one surface of the adhesive layer for adhesion with the battery cell to be attached to the outer surface of the battery cell.

The temperature sensor according to the present invention has a large contact with the battery cell by a flexible thin rectangular structure that can be bent in correspondence with the outer surface shape of the battery cell, and an adhesive layer formed on one surface to be attached to the outer surface of the battery cell. By forming an interface and eliminating the trouble of adding a separate adhesive or using a fixing member for attaching a temperature sensor to a battery cell, precise temperature measurement is possible, while shortening the manufacturing process of the battery pack and improving productivity. There is an advantage that can be improved.

The battery pack is manufactured by connecting a protection circuit or the like to a core pack in which a plurality of battery cells are arranged in series and / or in parallel. The battery cell may be a rectangular, pouch or cylindrical battery.

In the case of a notebook computer, a portable DVD, a small PC, etc., a battery pack in which a plurality of cylindrical secondary batteries are connected in series or in parallel and in series is widely used.

The temperature sensor is for measuring the temperature of such a battery cell, and examples of the temperature sensor may include a thermocouple or thermistor, but are not limited thereto. Can be.

The thermistor is a sensor for temperature measurement using a principle in which a resistance changes significantly even with a minute temperature change, and the temperature of the battery cell may be measured in real time through a thermistor installed on an outer surface of the battery cell.

The thermistor may be of a lead type and a chip type, with a lead type being particularly preferred.

The shape of the temperature sensor is not particularly limited, but by the flexible thin rectangular structure, the shape can be changed according to the shape of the outer surface of the battery cell, and the surface to be attached can be widened.

The area of the adhesive layer formed on one side of the temperature sensor is preferably 20% to 100% of the area of the attachment surface of the temperature sensor. The adhesive layer may be formed only on a part of the surface of one side of the temperature sensor, but when the adhesive layer is less than 20% of the area of the attachment surface, it is difficult to exert a desired adhesive force. It is desirable to have.

Examples of the adhesive layer include an acrylic polymer, a silicone resin, an epoxy resin, and the like, but are not limited thereto, and may be used in combination of two or more cases.

In one preferred example, the adhesive layer may be configured to include a thermally conductive material. Examples of the conductive material include metal powders, carbon powders, ceramic powders, and the like, but are not limited thereto, and may be used in combination of two or more cases.

As described above, the thermally conductive material included in the adhesive reduces the amount of heat dissipated to the outside during the conduction of heat from the battery cell to the temperature sensor, thereby enabling more accurate temperature measurement of the battery cell.

In some cases, the adhesive layer itself may be made of a thermally conductive adhesive, and the thermal conductivity of the thermally conductive adhesive may be preferably 1 W / mK or more, more preferably 5 W / mK or more. The upper limit value is not particularly limited under the conditions of exhibiting the desired adhesiveness and thermal conductivity.

Representative examples of such thermally conductive adhesives include epoxy adhesives having high thermal conductivity.

Such thermally conductive adhesives may, for example, have a property of being thermally cured or cured at room temperature with a low stress elastomer having toughness. Therefore, the thermally conductive adhesive can exert an adhesive force while increasing the efficiency of thermal conduction by filling the space between the heat generating body and the heat reducing body that cools the heat for thermal conduction.

Release paper may be further attached to the outer surface of the adhesive layer. The release paper may be attached to each of the temperature sensors, or may be made of a structure in which a plurality of the temperature sensors are attached to one release paper.

Since the release paper is attached to the outer surface of the adhesive layer of the temperature sensor, it is easy to handle the worker, and improves the work efficiency for attaching to the outer surface of the battery cell in the mass production process of the battery pack.

The present invention also provides a battery pack including the temperature sensor.

The temperature sensor may be mounted on one or more of a plurality of battery cells built in the pack case, and the temperature sensor may be connected to a controller for controlling the operation of the battery pack.

The control unit may be a form additionally added to the battery pack as an independent member, and may be a general battery management unit (BMU), a protective circuit module (PCM), and a battery management system (BMS) for controlling the operation of the battery pack.

The BMU is used in a notebook computer battery pack, the PCM (Protective Circuit Module) is a small battery pack, and the BMS (Battery Management System) is a safety device used in a large battery pack.

The position at which the control unit is mounted is not particularly limited, but for example, the control unit may be installed at a position adjacent to an inner surface of the pack case, and may have a structure in which an external connection terminal of the control unit is exposed to the outside through the pack case. .

Since the temperature sensor is made of a thin and flexible material, the temperature sensor may be bent and adhered along the shape of the outer surface of the battery cell.

The battery cell is not particularly limited as long as it is a secondary battery capable of charging and discharging. Preferably, the battery cell may be a lithium secondary battery. In this case, a temperature sensor is mounted on the outer surface of the battery cell, and a plurality of such battery cells are built in the pack case to form a lithium secondary battery battery pack.

A lithium secondary battery is comprised with a positive electrode, a negative electrode, a separator, lithium salt containing nonaqueous electrolyte, etc., for example.

The positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive agent, and a binder onto a positive electrode current collector, followed by drying, and optionally, a filler may be further added to the mixture.

The positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _2-x O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO _2, and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ , wherein M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3; Formula LiMn _2-x M _x O ₂ (wherein M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The negative electrode is also produced by coating and drying a negative electrode material on a negative electrode current collector, and as the negative electrode active material, for example, natural graphite, artificial graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nano Carbon and graphite materials such as tubes, fullerenes and activated carbons; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt, Ti which can be alloyed with lithium, and compounds containing these elements; Metals and their compounds and composites of carbon and graphite materials; Lithium-containing nitrides, and the like.

The separator is interposed between the anode and the cathode, an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally from 0.01 to 10 ㎛ ㎛, thickness is generally 5 ~ 300 ㎛. As such a separator, for example, a sheet, a nonwoven fabric, or the like made of an olefin polymer such as polypropylene having chemical resistance and hydrophobicity, glass fiber or polyethylene, or the like is used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

The electrolyte solution includes a lithium salt and a non-aqueous solvent, the lithium salt is dissolved in the non-aqueous solvent, and serves as a source of lithium ions in the battery to enable the operation of the basic lithium secondary battery, between the positive electrode and the negative electrode As a material that promotes the movement of lithium ions of, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₃ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ and the like can be used.

In addition, the non-aqueous organic solvent serves as a medium to move the ions involved in the electrochemical reaction of the battery. As the non-aqueous solvent, for example, N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyl Aprotic organic solvents such as laclactone and 1,2-dimethoxy ethane can be used. The mixing ratio in the case of mixing one or more of the organic solvents can be appropriately adjusted according to the desired battery performance, which can be widely understood by those skilled in the art.

The secondary battery according to the present invention can be manufactured by conventional methods known in the art. In addition, the structure of the positive electrode, the negative electrode and the separator in the secondary battery according to the present invention is not particularly limited, and, for example, each of these sheets in a winding type (winding type) or stacking (stacking type) cylindrical, rectangular or It may be inserted into a pouch type case.

With reference to the drawings that disclose some embodiments of the present invention in more detail below, this is for easy understanding of the present invention, the scope of the present invention is not limited thereto.

3 shows a temperature sensor according to an embodiment of the present invention.

Referring to FIG. 3, the temperature sensor 100 has a flexible thin rectangular structure for precise temperature measurement, and an adhesive layer for adhesion to a battery cell so that the temperature sensor 100 may be attached to an outer surface of a battery cell (not shown). 200 is formed on one surface.

Since the temperature sensor 100 has a flexible thin structure, the temperature sensor 100 may be deformed to correspond to the outer shape of the battery cell, and may form a high adhesive interface with the battery cell. Furthermore, since the adhesive layer 200 is formed on one surface of the temperature sensor 100, the operation of attaching the temperature sensor 100 to the outer surface of the battery cell can be easily performed.

4 shows a temperature sensor according to another embodiment of the present invention.

Referring to FIG. 4, the adhesive layer 200 formed on one surface of the temperature sensor 100 may be formed on the entire surface of the temperature sensor 100, or may be formed on a part of the surface of the temperature sensor 100. have.

Although the adhesive layer 200 may be formed only on a part of the surface of one side of the temperature sensor 100, when the adhesive layer 200 is less than 20% of the area of the adhesive surface, it may be difficult to exert a desired adhesive force.

5 and 6 illustrate a temperature sensor according to another embodiment of the present invention.

Referring to FIG. 5, a release paper 300 is additionally attached to an outer surface of the adhesive layer 200 of the temperature sensor 100. Since the adhesive layer 200 is sealed by the release paper 300, it is easy to handle the temperature sensor 100, and if necessary, the release paper 300 is removed so that the adhesive layer 200 faces the outer surface of the battery cell. The temperature sensor 100 can be easily attached to (not shown).

Referring to FIG. 6, a plurality of temperature sensors 100 are attached to one release paper 300. As such, when a plurality of temperature sensors 100 are attached to one release paper 300, the plurality of temperature sensors may be handled at a time in a battery pack manufacturing process, thereby increasing work efficiency.

7 shows the inside of the battery pack to which the temperature sensor according to another embodiment of the present invention is attached.

Referring to FIG. 7, the battery pack 400 includes a plurality of cylindrical battery cells 500 embedded in the pack case 600, and the cylindrical battery cells 500 are equipped with a temperature sensor 100. The temperature sensor 100 is connected to a controller 700 that controls the operation of the battery pack 400.

Since the temperature sensor 100 is made of a thin and flexible material, the temperature sensor 100 may be bent in close contact with the shape of the outer surface of the cylindrical battery cell 500.

The cylindrical battery cell 500 may be a lithium secondary battery, and a plurality of cylindrical battery cells 500 are built in the pack case 600, and the temperature sensor 100 is attached to the outer surface of the cylindrical battery cell 500. The lithium secondary battery battery pack 400 may be manufactured by connecting to the control unit 700.

As described above, the temperature sensor according to the present invention enables precise temperature measurement of the battery cell, and facilitates the mounting work of the temperature sensor on the battery cell, thereby greatly improving the manufacturing processability of the battery pack.

Those skilled in the art to which the present invention belongs will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

1 is a perspective view of a battery pack inside a battery cell to which a conventional temperature sensor is attached;

2 is a perspective view of a form in which an existing temperature sensor is attached to a battery cell after reinforcement of a sticker;

Figure 3 is a perspective view of the form of the temperature sensor according to one embodiment of the present invention as viewed from the lower side;

4 is a plan view of a temperature sensor in which an adhesive layer is formed according to one embodiment of the present invention;

Figure 5 is a perspective view of the form of the temperature sensor attached to the release paper according to an embodiment of the present invention as viewed from the lower side;

6 is a plan view of a form in which a plurality of temperature sensors are attached to one release paper according to one embodiment of the present invention;

7 is a perspective view of the inside of the battery pack is a battery cell is attached to the temperature sensor according to another embodiment of the present invention.

Claims (11)

A temperature sensor for measuring the temperature of a battery cell in a battery pack having a structure in which a plurality of battery cells are electrically connected and built in a pack case, and the temperature sensor is made of a flexible thin rectangular structure for precise temperature measurement. And a bonding layer formed on one surface of the battery cell to be attached to the battery cell so as to be attached to an outer surface of the battery cell. The temperature sensor according to claim 1, wherein the area of the adhesive layer is 20% to 100% of the area of the attachment surface of the temperature sensor. According to claim 1, wherein the adhesive layer is a temperature sensor, characterized in that made of one or two or more selected from the group consisting of acrylic polymer, silicone resin and epoxy resin. The temperature sensor of claim 1, wherein the adhesive layer includes a conductive material. The temperature sensor of claim 4, wherein the conductive material is one or more selected from the group consisting of metal powder, carbon powder, and ceramic powder. The temperature sensor according to claim 1, wherein the adhesive layer is made of a thermally conductive adhesive having a thermal conductivity of 1 W / mK or more. The temperature sensor according to claim 6, wherein the thermally conductive adhesive is made of a high thermal conductivity epoxy adhesive. The temperature sensor according to claim 1, wherein a release paper is further attached to an outer surface of the adhesive layer. The temperature sensor according to claim 1, wherein the temperature sensor has a structure in which a plurality of temperature sensors are attached to one release paper. A plurality of battery cells are built in the pack case, one or more of the battery cells is equipped with a temperature sensor according to any one of claims 1 to 9, wherein the temperature sensor is to operate the battery pack The battery pack is connected to the control part to control. The battery pack according to claim 10, wherein the battery cell is a lithium secondary battery.

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