KR20070081533A - Method for testing a welding condition of unit cell in medium and heavy battery pack - Google Patents

Abstract

A method for testing a welded state of unit cells in medium and heavy battery modules is provided to exactly judge a connection state of a coupling member for the unit cell in a simple automated method and to restrict the increase of testing time. In a battery module(100) comprising a plurality of unit cells(110), the first unit cell and the rest unit cells are connected to each other by making polarities of electrode terminals of the first unit cell and the rest unit cells different. And then, voltage of the first unit cell and the rest unit cells is successively or simultaneously measured. A connection state among the electrode terminals and a coupling member is checked by comparing voltage for each unit cell set in advance for the battery module, with the measured voltage.

Description

Method for Testing A Welding Condition of Unit Cell In Medium And Heavy Battery Pack}

1 is a perspective view of a cylindrical lithium ion battery 4P12S battery module according to an embodiment of the present invention;

2 is a schematic diagram briefly showing the polarity of a cylindrical secondary battery;

3 is a schematic diagram showing one bank composed of four cylindrical unit cells;

4 is a schematic view showing the arrangement of the cylindrical secondary battery 4P12S battery module;

5 is a schematic view showing the top and side surfaces of the connection structure of the connecting member in the cylindrical secondary battery 4P12S battery module;

6 is a circuit diagram illustrating a connection structure of a connection member in the battery module of FIG. 5;

FIG. 7 is a schematic diagram illustrating a connection method between a sensing pin of an upper sensing pin plate and an upper portion of a battery module according to an exemplary embodiment of the present disclosure; FIG.

8 is a circuit diagram of a sensing pin plate according to one embodiment of the present invention;

9 is a schematic diagram when a magnetic plate is applied according to an embodiment of the present invention.

The present invention relates to a method for inspecting the welding state of unit cells in a medium-large battery module, and more particularly, using a sensing pin plate connected to the electrode terminals of each unit cell at the same time. (Or banks of unit cells connected in parallel) and the other sensing pins are connected to opposite electrode terminals of the remaining unit cells, and the voltage of each unit cell is measured sequentially or simultaneously, By checking the difference between the pre-set voltages and the measured voltages, the connection state of the connection member to the electrode terminal is known and whether the connection state such as welding or soldering of the electrode terminal of the unit cell and the nickel plate is correct. It is about a test method that can be confirmed in a correct position in a short time.

Cylindrical secondary battery module is a high-capacity energy source, the use of which is diversified into not only notebook computers but also industrial tools or agricultural tools, and research is actively conducted as demand increases. When used in the tool, etc., it is mostly used as an energy source for driving a motor, and requires a battery pack having a high output and a large capacity. Therefore, in order to be a suitable structure for these motor drive energy sources, it is necessary to use a larger number of arrays and a larger number of cylindrical secondary batteries than the battery modules for notebook computers.

Current arrangements include 2P12S, 4P12S, and 7P12S, and more cylindrical battery arrays and numbers are expected to be applied for higher power and higher capacity applications in the future.

Each cylindrical cell is connected in parallel to a metal conductive terminal such as a nickel plate to form a bank, and between each bank is connected to a metal conductive terminal such as a nickel plate to form a single bank. Configure the battery module. At this time, spot welding is generally performed in order to connect the conductive terminal of the metal component on the (+) and (-) terminals of the battery.

In such a medium-large battery module, it is very important that the lead plates electrically connecting the unit cells and the terminals of the unit cells are securely bonded. If the welding is incomplete, the electrical contact is poor and the battery module does not reach the set voltage, and mechanical failure is also a cause of failure. However, it is difficult to determine whether such a weld joint is only by appearance.

Therefore, it is necessary to check whether welding is properly performed after spot welding. As the number of arrays and the number of batteries increases, the number of inspection points per battery module increases, and the inspection time increases in proportion to the number of batteries. In particular, where a large number of battery packs are produced, such as a mass production line, there is a need for a method capable of inspecting terminal welding in a short time.

Conventionally, after measuring the total voltage of the completed battery module without a separate method, it is common to use a method of checking the voltage of each unit battery again for a battery module smaller or larger than a predetermined voltage range. . As such a technique, a method (Japanese Patent Laid-Open No. 2003-123729) has been proposed in which a predetermined pressure is applied to an intermediate portion of a lead plate and then the voltage of the battery module is inspected. In this method, when a poor welding part is present in the battery module, the lead of the defective part is bent by the applied pressure, thereby disconnecting the battery connection, and as a result, the voltage is not detected so that the presence of the welding failure can be confirmed. . However, even if the presence of the welding defect is confirmed, since the position thereof is not known accurately, it is cumbersome to check the voltage of each unit cell again.

Therefore, there is an urgent need for the development of a new method for quickly and simply checking the connection state between the electrode terminal and the connection member of the unit cell in the battery module.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

After further research and various experiments, the inventors of the present application use a sensing pin plate connected to the electrode terminals of each unit cell at the same time, and the first sensing pin is connected to the electrode terminal of the first unit cell or bank. When the sensing pins are connected to the opposite electrode terminals of the remaining unit cells, when the voltage of each unit cell is measured sequentially or simultaneously, the welding failure position is quickly compared by comparing the preset voltages with the measured voltages. It was found that it can be confirmed. Moreover, such an inspection method has many advantages, such as an increase in the time required for inspection and no significant structural change of the inspection apparatus even when the battery module is composed of more unit cells for increasing output or capacity. It was confirmed that.

Therefore, the method for inspecting the welding state of the unit cells in the medium-large battery module according to the present invention, in the battery module consisting of a plurality of unit cells, the polarity of the electrode terminal of the first unit cell and the electrode terminals of the remaining unit cells In a differently connected state, the voltages of the first unit cell and the remaining unit cells are measured sequentially or simultaneously, and the voltage for each unit cell ("set voltage") preset for the battery module is compared with the measured voltage. And it provides a test method for checking the connection state of the electrode terminal and the connection member.

Such an inspection method of the present invention has an advantage in that it is possible to quickly cope with welding defects because the automated system can grasp the welding state between the electrode terminals for each unit cell or bank of unit cells connected in parallel at a short time.

The battery module applicable to the present invention may be formed by connecting the unit cells in series, in parallel, or in series and parallel manners. In a preferred embodiment, the unit cells include at least a series connection, and each unit cell connected for voltage measurement may be a unit cell of a bank in which two or more unit cells are connected in parallel. As a specific example, in the battery module of the 4P12S array, four unit cells are connected in parallel to form one bank, and the 12 banks are connected in series. In this case, the unit cells and the banks may be connected in series and in parallel using a metallic connection member such as a nickel plate.

In order to measure the voltage, the electrode terminals of the first unit cell and the electrode terminals of the remaining unit cells are connected to each other with different polarities, so that the electrode terminals may be connected at the same time.

Such simultaneous connection can be achieved by a sensing pin plate connected to the electrode terminals of each unit cell at the same time. In this case, the sensing pin plate may be applied to the upper and lower portions of the battery module, respectively. This is because the unit cells constituting the battery module are arranged with different polarities in order to be connected in series. In the method of connecting by the sensing pin plate, for example, the first sensing pin is connected to the positive terminal of the first unit cell, and the remaining sensing pins are connected to the negative terminal which is the opposite electrode terminal of the remaining unit cells. will be. Therefore, in the case of the battery module consisting of 12 banks, the first sensing pin is connected to the (+) terminal of the first bank, the sensing pin is connected to each of the remaining 12 (-) terminals.

In this state in which the electrode terminals of the unit cells are connected, the voltages of the first unit cell and the remaining unit cells may be measured sequentially or simultaneously. The sensing pin plate according to the present invention includes a connection switch for turning on and off a connection to a circuit for each sensing pin having a polarity opposite to that of the first sensing pin, thereby measuring voltage for each unit cell. To be.

As a preferable example of measuring voltage sequentially, in the case where the terminals are connected as described above, by connecting the connection switch connected to each of the (-) sensing pins from the pin closest to the (+) sensing pin by connecting On In each step, IR values are measured. Compared to the IR values of each preset and stored step, check the banks for which the IR value does not increase or the IR value suddenly increases and displays on the monitor. In reverse order from the above, the switch operation may be performed in the order close to the (-) sensing pin farthest from the (+) sensing pin.

When the measured voltage is greater than or equal to 10 to 30% of the upper and lower error range of the set voltage, it may be defined as a bad connection. At this time, if the allowable error range is set too large, there may be a problem that the connection failure may be overlooked. If the error range is set too small, welding may be performed again for a normal battery module which is not a connection failure such as a potential difference of the unit cell itself. It is not preferable because the productivity is lowered by checking the titration.

When the electrode terminals of the unit cells to be measured are partially opposed to each other, it is preferable to use the number of the sensing pin plates corresponding thereto. As described above, for example, 12 banks are connected in series. In the case of the battery module, the first sensing pin may be connected to the (+) terminal of the first bank, and the sensing pin may be connected to each of the remaining 12 (-) terminals.

The unit cell that can be used in the present invention may be a cylindrical or angular, pouch-type battery, of which the cylindrical battery is most preferred.

The present invention also provides an inspection apparatus capable of performing such a method.

An inspection apparatus according to the present invention includes one or more sensing pin plates including a plurality of sensing pins connected to electrode terminals of a plurality of unit cells, an IR meter for measuring voltage at each sensing pin, and each unit cell or bank. And a control unit for comparing the measured voltage and the set voltage to compare whether the voltage difference exceeds a predetermined range, and a display unit for displaying the processing result of the control unit.

The control unit is not particularly limited as long as it can perform data storage and voltage comparison as described above, and preferably, a computer including a PC.

Although the display unit is basically configured as a monitor for displaying the processing result of the control unit as visual information, in some cases, the display unit may include a speaker for providing audio information in addition to the visual information.

In one preferred example, a magnetic plate is further included between the electrode terminal of the unit cell and the sensing pin plate, so that the attraction pin can be more easily connected to the electrode terminal by a magnetic force.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the scope of the present invention is not limited thereto.

1 is a perspective view of a cylindrical secondary battery 4P12S battery module according to an embodiment of the present invention. Referring to FIG. 1, one bank 130 is formed of four cylindrical unit cells 110. Since the battery module 100 is a 4P12S array, the bank consists of a total of 12 banks and a total of 48 batteries. As the connecting member, the nickel plate 120 is welded to the positive and negative terminals of each bank 130, and the positive and negative terminals corresponding to adjacent banks are also welded at the same time. Configure module 100.

In FIG. 2, the polarity of the cylindrical secondary battery 110 is briefly displayed. The upper terminal is shown as a (+) terminal 111, and the lower terminal is represented as a (−) terminal 112.

In FIG. 3, one bank 130 composed of four unit cells is illustrated using the cylindrical battery 110 of FIG. 2 as a unit cell.

4 schematically shows an arrangement structure of a 4P12S battery module made of a cylindrical secondary battery. Referring to FIG. 4, each bank 130 is disposed in the same direction by being connected in parallel between the unit cells 110, and is connected in series between the banks 130 in an opposite direction, that is, in an alternate orientation. It can be seen.

FIG. 5 schematically illustrates a top and side surfaces of the connection structure of the nickel plate 120 of the cylindrical secondary battery 4P12S battery module of FIG. 4, and FIG. 6 illustrates a connection structure of the connection member illustrated in FIG. 5 as a circuit. It is. 5 and 6, the electrical connection structure of the 4P12S battery module and the connection structure of the nickel plate 120 can be confirmed.

FIG. 7 schematically illustrates a connection method of a sensing pin of an upper sensing pin plate and an upper portion of a battery module according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the upper sensing pin plate 210 having the seven sensing pins 201 and 202 and the lower sensing pin plate 220 having the six sensing pins 203 are respectively the battery module 100. Located at the top and bottom of the upper plate 210, the first sensing pin 201 is connected to the (+) terminal 111 of the first cell, the remaining 12 sensing in the upper and lower plates (210, 220) The pins 202 and 203 are connected to the negative terminal 112 of the unit cell 110. Therefore, the positive sensing pin 201 is connected to only one terminal terminal (+) 111 of the battery module 100, and the remaining twelve (-) sensing pins 202 and 203 are connected to (-) of each bank. ) Are connected to 12 terminals 112 respectively. Here, the contacts 113 to which the sensing pins 201, 202, and 203 connect to the unit cell 110 are connected to the electrode terminals 111 and 112 of the outer electrode from the nickel plate 120 to avoid connection with the nickel plate 120. ).

8 illustrates a circuit configuration of a sensing pin plate according to an embodiment of the present invention.

Referring to FIG. 8, the inspection apparatus 300 includes a sensing pin plate 200, an internal resistance (IR) measuring instrument 310, a PC 320, a monitor 330, and a speaker 340. The voltage is measured by the IR meter 310 at each step while sequentially operating the switches connected to each of the (-) sensing pins in order from 1 to 12. The PC 320 compares the IR value of each step stored therein with the measured value from the IR meter 310 to check the position of the bank in which the IR value is abnormal and displays it on the monitor 330. When the occurrence of the failure is confirmed, the PC 320 notifies the failure through the speaker 340, the manager refers to the information displayed on the monitor 330, and sends the battery module 100, the failure occurs to the welding process again Re-weld the terminal with the connection member that is not welded properly.

Figure 9 is a schematic diagram when the magnetic plate is applied according to another embodiment of the present invention.

9, the magnetic plate 350 is positioned between the electrode terminals 111 and 112 of the unit cell 110 and the sensing pin plates 201 and 202. Therefore, by pulling them to each other by the attraction force by the electromagnetic force, the connection of the sensing pins 201, 202, 203 to the electrode terminals 111, 112 can be easily achieved.

Due to the characteristics of the inspection method and the inspection apparatus as described above, the present invention, even if the number of unit cells and the number of unit cells required for manufacturing the battery module is increased, the number of batteries increased the inspection time of the electrode terminal welding It is possible to improve the productivity of the multi-array battery module and to ensure the reliability of the terminal assembly by providing a method that can be inspected within a very short time as in the prior art without being affected.

That is, as the arrangement and number of unit cells increase, the inspection point for whether the terminal welding per battery module increases, it is inevitable that the conventional inspection method for each terminal increases the inspection time in proportion to the number of batteries. However, if the inspection method of the present invention is applied, even a battery module having more than 7P12S array can be quickly inspected without increasing the inspection time.

In the above, a cylindrical battery is used as a unit cell to explain the inspection method according to the present invention. However, the present invention is not limited thereto and may be applied to a battery module using a square battery or a pouch battery. In addition, the present invention includes an apparatus capable of effectively performing the inspection method.

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

As described above, the method of inspecting the welding state of the unit cells in the medium-large battery module according to the present invention by measuring the voltage for each unit cell using a sensing pin plate, unlike the conventional method unit cell in a simple and automated method It is possible to accurately determine the connection state of the connection member to the, can be widely applied effectively to the medium-large battery pack required for medium-to-large devices, such as a power transmission device, a hybrid car.

Claims (14)

In a battery module composed of a plurality of unit cells, the voltages of the first unit cell and the remaining unit cells are sequentially or in a state in which the electrode terminals of the first unit cell and the electrode terminals of the remaining unit cells are connected with different polarities. Measuring at the same time and checking the connection state of the electrode terminal and the connection member by comparing the voltage for each unit cell ("setting voltage") previously set for the battery module with the measurement voltage. The method of claim 1, wherein the unit cells are connected in series, in parallel, or in series and in parallel. The method of claim 1, wherein the unit cells include a series-type connection, each unit cell connected for voltage measurement is a unit cell of a bank (bank) in which two or more unit cells are connected in parallel method of inspection. The inspection method according to claim 1, wherein the connection to the unit cell is performed at the same time. 5. The inspection method according to claim 4, wherein the simultaneous connection is achieved by a sensing pin plate connected to electrode terminals of each unit cell at the same time. The test method according to claim 1, wherein the voltage measurement is performed at the same time. The test method according to claim 1, wherein the measurement voltage is defined as a connection failure when the measured voltage is 10 to 30% or more of the upper and lower error ranges of the set voltage. The method of claim 5, wherein when the electrode terminals of the unit cells to be measured are partially disposed to face each other, the sensing pin plates are used as many as the corresponding number of the sensing pin plates. The method of claim 1, wherein the unit cell is a cylindrical battery. An apparatus capable of performing an inspection according to claim 1, comprising: one or more sensing pin plates including a plurality of sensing pins connected to respective electrode terminals of a plurality of unit cells, and measuring voltage at each of the sensing pins A control unit that includes information on an IR meter, a set voltage of each unit cell or a bank, and compares the measured voltage with a set voltage to compare whether a voltage difference exceeds a predetermined range, and displays a processing result of the control unit. An inspection apparatus, comprising a display unit. The test apparatus according to claim 10, wherein the control unit is a PC. The inspection apparatus according to claim 10, wherein the display unit is configured of a monitor which displays the processing result of the control unit as visual information. The test apparatus according to claim 12, wherein the display unit includes a speaker for providing auditory information in addition to the monitor. The test apparatus according to claim 10, wherein a magnetic plate is further included between the electrode terminal of the unit cell and the sensing pin plate.

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