Battery cell assembly including a thermistor and method of manufacturing same

Abstract

The present invention relates to a battery cell assembly including a cylindrical battery cell, a PCB disposed on an upper portion of the cylindrical battery cell, and a thermistor for measuring the temperature of the cylindrical battery cell, the thermistor being disposed on one side of the outer periphery of the PCB, and a method for manufacturing the same.

Description

[Technical field]

[0001] The present invention relates to a battery cell assembly including a thermistor and a manufacturing method thereof, and more particularly to a battery cell assembly including a thermistor capable of accurately measuring the temperature of a battery cell to ensure safety, and a manufacturing method thereof.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0092983 filed on July 27, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] 2. Description of the Related Art As the safety and capacity of rechargeable lithium secondary batteries are improved and increased rapidly, the types of devices that use the lithium secondary batteries as their energy source are increasing.

[0004] For example, the lithium secondary battery is not only widely used as an energy source for wireless mobile devices or wearable devices, which are multi-functional small products, but is also used as a medium- to large-sized battery pack for use as an energy source or energy storage system (ESS) for electric vehicles and hybrid electric vehicles, which are presented as an alternative to existing gasoline and diesel vehicles that cause air pollution.

[0005] The lithium secondary batteries are classified according to the shape of the battery case into cylindrical and prismatic secondary batteries in which an electrode assembly is built into a cylindrical or prismatic metal case, and pouch-type secondary batteries in which an electrode assembly is built into a pouch-type case made of an aluminum laminate sheet. Among them, cylindrical secondary batteries have the advantages of being relatively large in capacity and structurally safe.

[0006] Overheating of a battery cell can shorten the lifespan of the battery cell, and if the battery cell explodes due to thermal runaway, it can also affect the device in which the battery cell is installed.

[0007] Therefore, controlling the temperature of the battery cells has become an important issue.

[0008] FIG. 1 is a vertical cross-sectional view of a conventional battery cell assembly.

[0009] Referring to FIG. 1, the battery cell assembly has a PCB 120 positioned on top of a cylindrical battery cell 100, with the positive terminal of the cylindrical battery cell and a terminal of the PCB 120 connected via a first metal plate 102, and the negative terminal of the cylindrical battery cell and a terminal of the PCB 120 connected via a second metal plate 103.

[0010] A thermistor 130 for measuring the temperature of the cylindrical battery cell is located in the center of the PCB on the top surface of the PCB 120. However, when the thermistor is located in this manner, the thermistor 130 and the battery cell 100 do not come into contact with each other, so the thermistor 130 measures the temperature in the air, making it difficult to accurately measure the temperature of the battery cell 100.

[0011] In Patent Document 1, an electrode terminal protrudes from the outer periphery of one side of a pouch-type battery cell, and the electrode terminal is coupled to a connection terminal of a protection circuit board arranged at the upper end of the pouch-type battery cell. A thermistor for sensing the outer surface temperature of the battery cell is attached to the protection circuit board at an end portion close to the sealed outer periphery of the battery cell from which the electrode terminal protrudes, and thermally conductive tape is attached to the outer surfaces of the battery cell and the thermistor to physically connect them. Therefore, heat from the battery cell is conducted to the thermistor via the thermally conductive tape.

[0012] Patent Document 2 discloses a sensing module having a temperature sensor that is disposed on top of a cell stack composed of multiple battery cells arranged in the internal space of a module housing and that measures the temperature of the battery cells.

[0013] Thus, Patent Document 1 is a technology for measuring the temperature of a pouch-type battery cell, and Patent Document 2 is a technology for disposing a sensing module equipped with a temperature sensor inside a battery module housing. However, when a PCB is located at the upper end of a cylindrical battery cell, the reality is that a configuration is not presented that allows a thermistor placed on the PCB to directly / indirectly measure the temperature of the cylindrical battery cell. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Korean Patent Publication No. 10-2017-0023466 [Patent Document 2] Korean Patent Publication No. 10-2022-0030544 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention has been made to solve the above problems, and has an object to provide a battery cell assembly including a thermistor that can accurately measure the temperature of a battery cell by transferring heat from the battery cell to the thermistor via a thermally conductive adhesive attached to the thermistor, and a manufacturing method thereof. [Means for solving the problem]

[0016] To achieve this objective, a battery cell assembly according to the present invention includes a cylindrical battery cell, a PCB disposed on an upper portion of the cylindrical battery cell, and a thermistor for measuring the temperature of the cylindrical battery cell, the thermistor being disposed on one side of the outer periphery of the PCB.

[0017] The PCB may include a protrusion protruding from one outer periphery, and the thermistor may be mounted on the protrusion.

[0018] A thermally conductive adhesive may be applied to the thermistor, the PCB on which the thermistor is mounted, and a top surface of the cylindrical battery cell.

[0019] The thermistor may be in indirect contact with the cylindrical battery cell via the thermally conductive adhesive.

[0020] The thermally conductive adhesive may be any one selected from the group consisting of a silicon adhesive, an epoxy adhesive, and an acrylic adhesive, and may contain metal powder.

[0021] The internal space may further include a protective case in which the PCB and the thermistor are disposed.

[0022] The battery pack may further include a first metal plate connecting a positive terminal of the cylindrical battery cell to the PCB, and a second metal plate connecting a negative terminal of the cylindrical battery cell to the PCB.

[0023] The thermistor may be a chip-type thermistor.

[0024] The PCB may have a circular shape in plan view with one side cut away, a protrusion protruding outward from the outer periphery of the cut, and the thermistor may be located on the protrusion.

[0025] The PCB may have a structure in which a pair of slits parallel to each other are formed in a circular shape in plan view from the outer periphery toward the center, and the thermistor is located between the pair of slits.

[0026] The present invention provides a method for manufacturing the battery cell assembly, which may include the steps of preparing a cylindrical battery cell, arranging a PCB on the cylindrical battery cell, connecting a positive terminal and a negative terminal of the cylindrical battery cell to the PCB, mounting a thermistor on one side of the outer periphery of the PCB, and applying a thermally conductive adhesive to the thermistor, the PCB on which the thermistor is mounted, and an upper surface of the cylindrical battery cell.

[0027] The method may further include mounting a protective case on an upper portion of the cylindrical battery cell to protect the thermistor and the PCB.

[0028] The present invention provides a device including the battery cell assembly as an energy source.

[0029] Moreover, the present invention can also be provided in the form of a combination of various means for solving the above problems. Effect of the Invention

[0030] As described above, the battery cell assembly according to the present invention is capable of accurately measuring the temperature of the cylindrical battery cell since the temperature of the cylindrical battery cell can be transferred to the thermistor via the thermally conductive adhesive.

[0031] Also, by quickly and accurately determining the state of the cylindrical battery cells, a battery cell assembly with improved safety can be provided. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a vertical cross-sectional view of a conventional battery cell assembly. [Diagram 2] FIG. 2 is a perspective see-through view of a battery cell assembly according to the present invention. [Diagram 3] FIG. 3 is a vertical cross-sectional view of FIG. 2. [Figure 4] FIG. 2 is a plan view of an embodiment of a PCB in accordance with the present invention. [Diagram 5]1 is a graph showing the deviation between thermistor temperature and cylindrical battery cell temperature during charging in a comparative example and an example. [Figure 6] 1 is a graph showing the deviation between thermistor temperature and cylindrical battery cell temperature during a discharge process in a comparative example and an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that enables a person having ordinary skill in the art to which the present invention pertains to easily carry out the present invention. However, when describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations may unnecessarily obscure the gist of the present invention, and the detailed description will be omitted.

[0034] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0035] Furthermore, descriptions that limit or add specific elements are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0036] Moreover, throughout the description and claims of the present invention, the singular includes the plural unless specifically stated otherwise.

[0037] Furthermore, throughout the description of the present invention and the claims, unless otherwise stated, "or" includes "and." Thus, "including A or B" means three cases: including A, including B, or including both A and B.

[0038] The invention will now be explained with reference to the drawings and with reference to detailed embodiments.

[0039] FIG. 2 is a perspective view of a battery cell assembly according to the present invention, and FIG. 3 is a vertical cross-sectional view of FIG.

[0040] Referring to Figures 2 and 3, a battery cell assembly according to the present invention includes a cylindrical battery cell 100, a PCB 120 arranged on top of the cylindrical battery cell 100, and a thermistor 130 for measuring the temperature of the cylindrical battery cell 100, where the thermistor 130 may be arranged on one side of the outer periphery of the PCB 120.

[0041] The thermistor 130 has an electrical property in which its resistance changes depending on the temperature of the cylindrical battery cell, so the temperature of the cylindrical battery cell 100 can be estimated from the resistance value of the thermistor 130. The PCB 120 is a component for measuring the voltage, temperature, etc. of the cylindrical battery cell 100, and the temperature of the cylindrical battery cell 100 can be measured from the resistance value obtained via the thermistor 130.

[0042] The PCB 120 includes a positive terminal portion and a negative terminal portion. The positive terminal portion is connected to a top cap, which is the positive terminal of the cylindrical battery cell 100, via a first metal plate 102, and the negative terminal portion is connected to a bottom of the cylindrical can, which is the negative terminal of the cylindrical battery cell 100, via a second metal plate 103.

[0043] The present invention is configured such that the thermistor 130 is placed on the outer periphery of one side of the PCB 120 and a thermally conductive adhesive 140 is attached to the thermistor 130, thereby enabling thermal conduction between the thermistor 130 and the cylindrical battery cell 100 via the thermally conductive adhesive 140.

[0044] Thus, the PCB 120 includes a protrusion protruding from one outer periphery, and the thermistor 130 may be mounted and attached onto said protrusion.

[0045] A thermally conductive adhesive 140 may now be applied to the thermistor 130, the PCB 120 on which the thermistor is mounted, and the top surface 101 of the cylindrical battery cell.

[0046] That is, when a predetermined amount of thermally conductive adhesive 140 is applied to the thermistor 130 mounted on the PCB 120 so that the thermally conductive adhesive 140 contacts the top surface 101 of the cylindrical battery cell, the thermistor 130 can indirectly contact the cylindrical battery cell 100 via the thermally conductive adhesive 140.

[0047] Therefore, heat is transferred from the cylindrical battery cell 100 to the thermistor 130 via the thermally conductive adhesive 140 , so that the thermistor 130 can accurately measure the temperature of the cylindrical battery cell 100 .

[0048] The thermally conductive adhesive may be any one selected from the group consisting of a silicon adhesive, an epoxy adhesive, and an acrylic adhesive, and may contain metal powder.

[0049] The metal powder contains a metal having excellent thermal conductivity in powder form, and may contain, for example, aluminum, copper, gold, silver, tungsten, zinc, brass, nickel, bronze, carbon steel, or a combination thereof.

[0050] The thermistor 130 can be mounted on the upper surface of the PCB 120 and can be a chip-type thermistor. Conventionally, wire-type or FPCB-type thermistors have been used to measure the temperature of a top plate or a cylindrical can of a cylindrical battery cell, but the present invention uses a chip-type thermistor to reduce costs.

[0051] A protective case 110 may be disposed on the cylindrical battery cell 100. The protective case 110 may have an open bottom, a circular top, side surfaces extending vertically from the top, and a hollow interior.

[0052] The protective case 110 is configured to cover the PCB 120 and thermistor 130, and is attached to the upper part of the cylindrical battery cell 100. Therefore, the protective case 110 can protect the PCB 120 and thermistor 130 disposed in the internal space of the protective case 110 from external impact.

[0053] FIG. 4 is a plan view of an embodiment of a PCB according to the present invention.

[0054] Referring to Figure 4, (a) is a plan view of a PCB 120, a thermistor 130 attached thereto, and a thermally conductive adhesive 140 according to a first embodiment, and (b) is a plan view of a PCB 120, a thermistor 130 attached thereto, and a thermally conductive adhesive 140 according to a second embodiment.

[0055] In the first embodiment of FIG. 4(a), the PCB 120 has a circular shape on a plane with one side cut, and a protrusion 121 is formed that protrudes outward from the outer periphery of the cut, and the thermistor 130 is located in the protrusion 121.

[0056] Although FIG. 4( a ) shows the thermistor 130 as being located in the center of the protrusion 121 , the thermistor 130 can be located at the protruding end of the protrusion 121 .

[0057] In the first embodiment of FIG. 4(a), when the thermally conductive adhesive 140 is applied to completely cover the protrusion 121 and thermistor 130, the thermally conductive adhesive 140 can be applied up to the top surface of the cylindrical battery cell.

[0058] In the second embodiment of FIG. 4( b ), a pair of slits 122 that are circular in shape on a plane and parallel to each other are formed in a PCB 120 from the outer periphery toward the center, and a thermistor 130 is positioned between the pair of slits 122 .

[0059] In the second embodiment, when the thermally conductive adhesive 140 is applied to completely cover the space located between the slits 122 of the PCB 120 and the thermistor 130, the thermally conductive adhesive 140 can be applied up to the top surface of the cylindrical battery cell.

[0060] In the battery cell assembly according to the present invention, the shape of the PCB is not limited to the shape shown in Fig. 4, and may be configured in various shapes depending on the shape and size of the circuit printed on the PCB. For example, it goes without saying that the thermistor may be located on the outer periphery of one side of a planar polygonal plate-shaped PCB.

[0061] A manufacturing method of a battery cell assembly according to the present invention may include the steps of preparing a cylindrical battery cell and placing a PCB on top of the cylindrical battery cell, connecting a positive terminal and a negative terminal of the cylindrical battery cell to the PCB, mounting a thermistor on one side of the outer periphery of the PCB, and applying a thermally conductive adhesive to the thermistor, the PCB on which the thermistor is mounted, and an upper surface of the cylindrical battery cell.

[0062] When a predetermined amount of thermally conductive adhesive is applied to a thermistor mounted on a PCB so that the thermally conductive adhesive contacts the top surface of a cylindrical battery cell, the thermistor can be indirectly in contact with the cylindrical battery cell via the thermally conductive adhesive.

[0063] The method may further include mounting a protective case on an upper portion of the cylindrical battery cell to protect the thermistor and the PCB.

[0064] In the battery cell assembly according to the present invention, the PCB and the thermistor can be protected by the protective case, and heat can be transferred from the cylindrical battery cell to the thermistor via the thermally conductive adhesive, so that the temperature of the cylindrical battery cell can be accurately measured.

[0065] In this manner, the battery cell assembly according to the present invention can accurately measure the temperature of the cylindrical battery cell and grasp the condition of the cylindrical battery cell, and therefore, when included as an energy source of a device exposed to a high-temperature environment, the function of the battery cell assembly according to the present invention can be effectively demonstrated.

[0066] The present invention will be described below with reference to examples, which are for easier understanding of the present invention and are not intended to limit the scope of the present invention.

[0067] <Comparative Example> As in the battery cell assembly according to the prior art shown in FIG. 1, a thermistor for measuring the temperature of a cylindrical battery cell was disposed on the upper surface of the PCB at the center of the PCB.

[0068] While charging and discharging the battery cell assembly, the temperature of the thermistor and the temperature of the cylindrical battery cell were measured, respectively.

[0069] This makes it possible to obtain the deviation (ΔT) between the temperature of the thermistor and the temperature of the cylindrical battery cell.

[0070] <Example> As shown in Fig. 2, a thermistor for measuring the temperature of a cylindrical battery cell was disposed on the outer periphery of one side of the upper surface of a PCB, and a thermally conductive adhesive was applied to the thermistor, so that the thermistor and the cylindrical battery cell were indirectly contacted with each other via the thermally conductive adhesive.

[0071] The heat conductive adhesive used was a silicone adhesive to which aluminum powder had been added.

[0072] While charging and discharging the battery cell assembly, the temperature of the thermistor and the temperature of the cylindrical battery cell were measured, respectively.

[0073] This makes it possible to obtain the deviation (ΔT) between the temperature of the thermistor and the temperature of the cylindrical battery cell.

[0074] FIG. 5 is a graph showing the deviation (ΔT) between the thermistor temperature and the cylindrical battery cell temperature during the charging process in the comparative example and the example, and FIG. 6 is a graph showing the deviation (ΔT) between the thermistor temperature and the cylindrical battery cell temperature during the discharging process in the comparative example and the example.

[0075] 5 and 6, it can be seen that ΔT measured in the comparative example is greater than ΔT measured in the example throughout the entire charging process, indicating that the thermistor temperature measured in the comparative example does not accurately reflect the temperature of an actual cylindrical battery cell.

[0076] During the discharge process, the ΔT values ​​measured in the Comparative Example and the Example are almost the same up to about 500 seconds, but after that, the ΔT value measured in the Comparative Example is larger than the ΔT value measured in the Example, and it can be seen that the difference in the ΔT values ​​gradually increases as time increases.

[0077] Thus, in the comparative example in which no thermally conductive adhesive was used, the difference between the temperature measured by the thermistor and the actual temperature of the cylindrical battery cell increased as time increased, making it difficult to trust the accuracy of the thermistor temperature.

[0078] On the other hand, when the thermistor and the cylindrical battery cell are in indirect contact with each other using a thermally conductive adhesive as in the present invention, it is found that the temperature of the cylindrical battery cell can be measured relatively accurately.

[0079] In this way, the present invention limits the placement position of the thermistor to the outer periphery on one side of the top surface of the PCB, and applies thermally conductive adhesive to the thermistor and the top surfaces of the cylindrical battery cells, thereby providing a battery cell assembly with improved safety by quickly and accurately determining the temperature of the cylindrical battery cells.

[0080] Those skilled in the art will appreciate that based on the above content, various applications and modifications within the scope of the present invention will be possible. [Explanation of symbols]

[0081] 100 Cylindrical Battery Cells 101 Top surface of cylindrical battery cell 102 1st Metal Plate 103 Second Metal Plate 110 Protective Case 120 PCB 121 Protrusion 122 Slit 130 Thermistor 140 Thermally conductive adhesive

Claims

1. 1. A battery cell assembly comprising: A cylindrical battery cell; A PCB disposed on an upper portion of the cylindrical battery cell; a thermistor for measuring the temperature of the cylindrical battery cell; Including, The thermistor is disposed on one side of the PCB. Battery cell assembly.

2. The PCB includes a protrusion protruding from an outer periphery on one side, The thermistor is mounted on the protrusion. The battery cell assembly of claim 1 .

3. A thermally conductive adhesive is applied to the upper surfaces of the thermistor, the PCB on which the thermistor is mounted, and the cylindrical battery cell. The battery cell assembly of claim 1 .

4. The thermistor is in indirect contact with the cylindrical battery cell via the thermally conductive adhesive. The battery cell assembly of claim 3 .

5. The thermally conductive adhesive is any one selected from the group consisting of a silicon adhesive, an epoxy adhesive, and an acrylic adhesive, and contains a metal powder. The battery cell assembly of claim 3 .

6. The battery cell assembly further comprises: a protective case having an internal space in which the PCB and the thermistor are disposed; The battery cell assembly of claim 1 .

7. The battery cell assembly further comprises: a first metal plate connecting the positive terminal of the cylindrical battery cell and the PCB; a second metal plate connecting the negative terminal of the cylindrical battery cell and the PCB; The battery cell assembly of claim 1 .

8. The thermistor is a chip-type thermistor. The battery cell assembly of claim 1 .

9. The PCB is It is a circular shape in plan view with one side cut off, A protrusion is formed protruding outward from the cut outer periphery, The thermistor is located on the protruding portion. The battery cell assembly of claim 1 .

10. The PCB is A pair of slits parallel to each other on a circular plane are formed from the outer periphery toward the center, The thermistor is disposed between the pair of slits. The battery cell assembly of claim 1 .

11. A method for manufacturing a battery cell assembly according to any one of claims 1 to 10, comprising the steps of: providing a cylindrical battery cell and placing a PCB on top of the battery cell; connecting a positive terminal and a negative terminal of the cylindrical battery cell to the PCB; mounting a thermistor on one side of the PCB; applying a thermally conductive adhesive to the thermistor, the PCB on which the thermistor is mounted, and a top surface of the cylindrical battery cell; A method comprising:

12. The method further comprises: and mounting a protective case on an upper portion of the cylindrical battery cell to protect the thermistor and the PCB. The method of claim 11.

13. A device comprising a battery cell assembly according to any one of claims 1 to 10 as an energy source.

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