Battery module

Abstract

To provide a battery module capable of suppressing the deterioration of measurement accuracy of a battery state by covering positive and negative electrodes with a cylindrical first magnetic shield.SOLUTION: A battery module 1A includes a cylindrical first magnetic shield 40 covering a positive electrode tab 12a and a negative electrode tab 13, and a cell state monitoring circuit board 50 for monitoring the state of a battery cell 10a and a battery cell 10b. The cell state monitoring circuit board is a printed wiring board, and includes a substrate fixed on an external surface of the first magnetic shield 40, and a cell state monitoring circuit formed on the substrate. The cell state monitoring circuit includes response voltage signal output means, cell current signal output means, and cell state diagnosis means for diagnosing the state of the battery cells from the outputs of the response voltage signal output means and the cell current signal output means.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to a battery module. [Background technology]

[0002] A battery monitoring device is known that monitors the state of a battery cell by calculating the complex impedance of the battery cell based on the response signal to an AC signal (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-18133 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, the battery monitoring devices described above have a problem in that the accuracy of battery status measurement is reduced due to electromagnetic induction noise caused by the current flowing through the cell tabs and busbars of the battery cells.

[0005] The problem that this invention aims to solve is to provide a battery module that can suppress the decrease in the accuracy of battery state measurement. [Means for solving the problem]

[0006] The present invention solves the above problem by covering the positive and negative electrodes of the battery module with a cylindrical first magnetic shield. [Effects of the Invention]

[0007] According to the present invention, the first magnetic shield can block electromagnetic induction noise from the positive and negative electrodes, thereby suppressing a decrease in the accuracy of battery state measurement. [Brief explanation of the drawing]

[0008] [Figure 1] Fig. 1 is a perspective view showing an example of the battery module according to the first embodiment. [Figure 2] Fig. 2(a) is a plan view showing an example of the battery module according to the first embodiment, and Fig. 2(b) is a front view showing an example of the battery module. [Figure 3] Fig. 3(a) is a plan view showing an example of the battery cell according to the first embodiment, and Fig. 3(b) is a plan view showing an example of the cell state monitoring circuit board according to the first embodiment. [Figure 4] Fig. 4(a) is a perspective view showing an example of the response voltage signal connecting means according to the first embodiment, Fig. 4(b) is an explanatory view showing an example of a connection method between the response voltage signal connecting means and positive and negative tabs, and Fig. 4(c) is an explanatory view explaining the effect obtained by the response voltage signal connecting means. [Figure 5] Fig. 5 is an explanatory view showing an example of a method for detecting a current flowing through a battery cell according to the first embodiment. [Figure 6] Fig. 6(a) is an explanatory view explaining a magnetic field generated around the battery cell according to the first embodiment, and Fig. 6(b) is an explanatory view explaining the shielding effect obtained by the first magnetic shield according to the first embodiment. [Figure 7] Fig. 7 is a front view showing an example of the battery module according to the first modification. [Figure 8] Fig. 8(a) is a front view showing an example of the battery module according to the second modification, and Fig. 8(b) is a circuit diagram showing an example of the battery module. [Figure 9] Fig. 9(a) is a front view showing an example of the battery module according to the third modification, and Fig. 9(b) is a circuit diagram showing an example of the battery module. [Figure 10] Fig. 10(a) is a plan view showing an example of the battery module according to the second embodiment, and Fig. 10(b) is a front view showing an example of the battery module. [Figure 11] Fig. 11 is an exploded perspective view showing an example of the battery module according to the third embodiment. [Figure 12] Fig. 12 is a circuit diagram showing an example of a cell state monitoring circuit according to the third embodiment. [Figure 13] Fig. 13(a) is a front view showing an example of a cell state monitoring circuit board according to the third embodiment, Fig. 13(b) is a front view showing an example of a cell state monitoring circuit board according to a fifth modification, and Fig. 13(c) is a front view showing an example of a cell state monitoring circuit board according to a fifth modification. [Figure 14] Fig. 14 is an exploded cross-sectional view showing an example of a battery module according to the third embodiment. [Figure 15] Fig. 15(a) is a front view showing an example of a cell state monitoring circuit board according to a sixth modification, Fig. 15(b) is a front view showing an example of a cell state monitoring circuit board according to a seventh modification, and Fig. 15(c) is a front view showing an example of a cell state monitoring circuit board according to an eighth modification. MODES FOR CARRYING OUT THE INVENTION

[0009] <<First Embodiment>> A first embodiment of the battery module according to the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of the battery module according to the first embodiment, Fig. 2(a) is a plan view showing an example of the battery module, and Fig. 2(b) is a front view showing an example of the battery module. For convenience of explanation, the illustration of the module cover is omitted in Fig. 2(a), and the illustration of the front cover of the module cover is omitted in Fig. 2(b).

[0010] As shown in Figs. 1 to 2(b), the battery module 1A includes a plurality of battery cells 10a, 10b, a bus bar 20, external terminals 30, a plurality of (two in this example) first magnetic shields 40, a plurality of (two in this example) cell state monitoring circuit boards 50, a plurality of (two in this example) response voltage signal connecting means 60, a plurality of (two in this example) spacer-supporting members 70, a fixing means 80, and a module cover 90.

[0011] As shown in Figure 2(b), multiple battery cells 10a and 10b are stacked on top of each other via two spacer / support members 70. In this embodiment, battery cells 10a and 10b have the same configuration. Therefore, the configuration of battery cell 10a will be described as representative.

[0012] Figure 3(a) is a plan view showing an example of a battery cell 10a in the first embodiment. The battery cell 10a is, for example, a lithium-ion secondary battery. In this embodiment, a flat laminate film lithium-ion secondary battery is exemplified as the battery cell 10a. This battery cell 10a has a power generation element in which a positive electrode layer, a negative electrode layer, and a separator are laminated and filled with electrolyte, a positive electrode tab 12 connected to the positive electrode layer, a negative electrode tab 13 connected to the negative electrode layer, and an outer casing member 11 that houses and seals these. Although a detailed explanation of the materials included in the lithium-ion secondary battery and the battery structure is omitted, well known battery materials and structures can be applied to lithium-ion secondary batteries.

[0013] The positive and negative electrode tabs 12 and 13 of the battery cells 10a and 10b are made of plate-shaped metal members. These positive and negative electrode tabs 12 and 13 extend from the same side of the outer casing of the battery cell 10a so as to be adjacent to each other. As shown in Figure 2(b), these positive and negative electrode tabs 12 and 13 are each connected to a busbar 20. The busbar 20 is made of plate-shaped metal members. This busbar 20 electrically connects the battery cells 10a and 10b, and also electrically connects the battery cells 10a and 10b to the external terminals 30 (positive electrode terminal 31, intermediate terminal 32, negative electrode terminal 33). In this embodiment, the positive electrode tab 12, the busbar connected to the positive electrode tab 12, and the positive electrode terminal 32 correspond to an example of a "positive electrode" in the present invention, and the negative electrode tab 13, the busbar connected to the negative electrode tab 13, and the negative electrode terminal 33 correspond to an example of a "negative electrode" in the present invention.

[0014] As shown in Figure 2(b), the busbar 20 includes a positive busbar 21, an intermediate busbar 22, and a negative busbar 23. One end of the positive busbar 21 is connected to the positive tab 12 of the battery cell 10a, while the other end of the positive busbar 21 is connected to the positive terminal 31 of the external terminal 30. One end of the intermediate busbar 22 is connected to the negative tab 13 of the battery cell 10a, while the other end of the intermediate busbar 22 is connected to the positive tab 12 of the battery cell 10b. The central part of the intermediate busbar 22 is connected to the intermediate terminal 32. One end of the negative busbar 23 is connected to the negative tab 13 of the battery cell 10b, while the other end of the negative busbar 23 is connected to the negative terminal 33. The positive and negative tabs 12, 13 and the busbar 20 are joined to each other by, for example, ultrasonic bonding. Furthermore, the busbar 20 and the external terminal 30 are connected to each other, for example, by overlapping the screw holes provided on the busbar 20 and the external terminal 30 and fastening them with bolts.

[0015] As shown in Figures 2(a) and 2(b), the first magnetic shield 40 covers the positive and negative electrode tabs 12 and 13 of the battery cells 10a and 10b, and a portion of the busbar 20, with the positive and negative electrode tabs 12 and 13 and the busbar 20 housed in the internal space of the first magnetic shield 40. A portion of the busbar 20 near the connection point with the external terminal 30 protrudes slightly from the first magnetic shield 40.

[0016] The first magnetic shield 40 is a hollow cylindrical member having openings at both ends. One end of the first magnetic shield 40 is fixed to the outer casing member 11 of the battery cells 10a and 10b, and the other end of the first magnetic shield 40 is a free end. The first magnetic shield 40 may be fixed to the outer casing member by being sandwiched between the upper laminate film and the lower laminate film when an outer casing member composed of an upper laminate film and a lower laminate film is used, for example. Alternatively, it may be fixed to the outer casing member by a fixing member such as an adhesive.

[0017] The first magnetic shield 40 includes a magnetic layer composed of at least a magnetic material. The magnetic material included in this first magnetic shield 40 is preferably a soft magnetic material. Since soft magnetic materials have low magnetic resistance at low frequencies (high permeability), they can enhance the shielding effect against electromagnetic waves in the low frequency band. Specifically, as this soft magnetic material, low-frequency magnetic shielding sheets (e.g., 1383 manufactured by 3M Japan Ltd., FM SHIELD® manufactured by Hitachi Metals Ltd.), plate-shaped ferrite cores (e.g., Soft Ferrite manufactured by Hitachi Metals Ltd.), magnetic paint (e.g., Dotite manufactured by Fujikura Chemicals Co., Ltd.), iron plates, or silicon steel plates (e.g., Finemet® manufactured by Hitachi Metals Ltd.) can be used. When a conductive material such as metal is used as the magnetic material, the first magnetic shield 40 may be covered with an insulating material to prevent short circuits with the positive and negative electrode tabs 12 and 13.

[0018] The type of soft magnetic material can be appropriately selected according to the purpose. For example, a low-frequency magnetic shielding sheet has a high shielding effect against low-frequency electromagnetic waves per unit thickness, so the thickness of the first magnetic shield 40 can be set to be thin. Also, a plate-shaped ferrite core is easy to process, has electrical insulation properties, and can reduce mass production costs. If a magnetic paint is used, the shielding effect can be easily imparted to the member to which the magnetic paint is applied, and the shielding effect can also be easily imparted to a surface with a three-dimensional shape. When using a magnetic paint as the soft magnetic material, for example, a magnetic layer may be formed by applying the magnetic paint to the surface of a cylindrical resin member. Also, if an iron plate or silicon steel plate is used, mass production costs can be reduced.

[0019] A cell state monitoring circuit board 50 is provided on the outer surface of the first magnetic shield 40. Each cell state monitoring circuit board 50 has the function of monitoring the state of battery cells 10a and 10b, and in this embodiment, it has the function of monitoring the state of health (SOH) of the battery cells 10a and 10b. Thus, in this embodiment, the battery module 1A is equipped with a plurality of cell state monitoring circuit boards 50, one for each battery cell 10a and 10b.

[0020] In this embodiment, an example is given of using electrochemical impedance spectroscopy (EIS) as a method for monitoring the state of degradation (SOH). In this electrochemical impedance spectroscopy, the internal resistance of battery cells 10a and 10b is calculated based on the response voltage from battery cells 10a and 10b and the current flowing through battery cells 10a and 10b when an AC signal of a predetermined frequency is applied to the battery module 1A from an external terminal 30 using an external power supply. Then, a degradation diagnosis is performed based on this internal resistance data. For example, the state of the battery cells can be diagnosed by referring to predefined calibration characteristics of the state of degradation (SOH) and internal resistance (HFR).

[0021] In this case, the measurement frequency of the electrochemical impedance may be a low frequency of 100 kHz or less. Although the characteristics change depending on the cell composition, the approximate state of a part of the battery cell can be identified by the frequency band. For example, in the DC to 100 Hz band, the state of the positive electrode is predominantly reflected in the impedance value, in the range of several tens to several kHz, the state of the negative electrode is predominantly reflected, and in the range of 1 kHz to 100 kHz, the positive and negative electrode states gradually diminish, and the state of the electrolyte begins to appear. Thus, it has been found that by measuring the impedance in the target frequency band during cell state monitoring, the state of the corresponding part can be diagnosed. On the other hand, there is a characteristic that the shielding effect is difficult to obtain at lower frequencies. Focusing on this characteristic, the present invention provides a first magnetic shield 40 made of the soft magnetic material described above in order to improve the impedance measurement resolution in the frequency band of approximately 100 kHz or less, which contains useful information.

[0022] Figure 3(b) is a plan view showing an example of a cell state monitoring circuit board 50 in the first embodiment. This cell state monitoring circuit board 50 is a printed circuit board and includes a base material 51 fixed to the outer surface of the first magnetic shield 40 and a cell state monitoring circuit 52 formed on the base material 51. The base material 51 is a resin plate and is attached to the first magnetic shield 40 via an adhesive or the like. The adhesive in this embodiment corresponds to an example of an "insulator" in the present invention.

[0023] In this embodiment, it is preferable that the thickness of the adhesive be 1 mm or more. The positive and negative electrode tabs 12, 13, the first magnetic shield 40, and the cell state monitoring circuit board 50 are all often covered with insulating material to prevent electrical short circuits. However, as the frequency of the electrical signal flowing through the battery cell increases (becomes high frequency), the insulation resistance of the insulating material decreases, making signal leakage more likely. In contrast, by setting the thickness of the adhesive (insulator) to 1 mm or more, measurement errors in the cell state monitoring circuit 52 caused by leaked signals can be suppressed. In other words, since the response voltage signal of the cell is a weak signal of 1 mV or less, high-precision cell state monitoring can be achieved by implementing noise countermeasures not only with magnetic shielding but also with electrostatic coupling. Air may also be used as this insulator. That is, an air gap of 1 mm or more in thickness may be formed between the region of the base material 51 on which the cell state monitoring circuit 52 is formed and the first magnetic shield 40. In this case, for example, by applying adhesive only to the outer periphery of the surface of the base material 51 facing the first magnetic shield 40, and bonding only the outer periphery of that facing surface to the first magnetic shield 40, a gap can be formed between the region of the base material 51 where the cell state monitoring circuit 52 is formed and the first magnetic shield 40.

[0024] The cell state monitoring circuit 52 includes a response voltage signal output means 521, a cell current signal output means 522, and a cell state diagnostic means 523. The response voltage signal output means 521 detects the voltage between the positive and negative electrode tabs 12 and 13 when an AC signal is applied to the battery module 1A, and outputs a voltage signal indicating this voltage to the cell state diagnostic means 523.

[0025] The response voltage signal output means 521 is electrically connected to the positive and negative electrode tabs 12 and 13 via the response voltage signal connection means 60 (see Figure 2(b)). The response voltage signal connection means 60 extends vertically from the positive and negative electrode tabs 12 and 13 toward the cell state monitoring circuit 52, penetrating the first magnetic shield 40. The cell state monitoring circuit 52 is located near the response voltage signal connection means 60, and in this embodiment, the cell state monitoring circuit 52 is directly connected to the upper end of the response voltage signal connection means 60.

[0026] Figure 4(a) is a perspective view showing an example of a response voltage signal connection means in the first embodiment, Figure 4(b) is an explanatory diagram showing an example of a method for connecting the response voltage signal connection means to the positive and negative electrode tabs, and Figure 4(c) is an explanatory diagram explaining the effects of the response voltage signal connection means. The response voltage signal connection means 60 includes a connection terminal holding member 61, a positive electrode connection terminal 62, a positive electrode wiring 63, a positive electrode connection terminal 64, and a negative electrode wiring 65. Note that in Figure 4(b), the connection terminal holding member 61 is omitted from the illustration for convenience.

[0027] The terminal retaining member 61 is made of an insulating material such as resin and has a cubic shape with recesses (positive electrode side recess 611 and negative electrode side recess 612) formed on two opposing sides. A locating key portion 613 is formed between the positive and negative electrode recesses 611 and 612. This locating key portion 613 is a part that fits into the gap between the positive and negative electrode tabs 12 and 13 shown in Figure 4(b), and the two guide walls 614 of the locating key portion 613 abut against the sides of the positive and negative electrode tabs 12 and 13, thereby positioning the positive electrode terminal 62 and the positive electrode terminal 64 in the horizontal direction.

[0028] In the positive electrode recess 611, a portion of the positive electrode connection terminal 62, made of a conductive material, is embedded in the connection terminal holding member 61. The positive electrode connection terminal 62 is made of a substantially U-shaped conductive material, and the positive electrode tab 12 is press-fitted into this U-shaped groove, thereby making contact with the positive electrode tab 12 and establishing an electrical connection. This positive electrode connection terminal 62 is electrically connected to the positive electrode tab 12 in the region near point a of the first proximity portion 12a. The first proximity portion 12a is the portion of the positive electrode tab 12 that is close to the negative electrode tab 13, and in this embodiment, it is the portion adjacent to the negative electrode tab 13 of the same battery cell.

[0029] One end of the positive electrode wiring 63 is connected to this positive electrode connection terminal 62. As shown in Figure 4(a), the portion of the positive electrode wiring 63 near the connection point with the positive electrode connection terminal 62 is embedded in the connection terminal holding member 61. This positive electrode wiring 63 penetrates the first magnetic shield 40, and as will be described later, the other end is electrically connected to the response voltage signal output means 521.

[0030] As shown in Figure 4(b), the positive electrode wiring 63 includes a conductive conductor 631 and an insulating tube 632 covering the conductor 631. Both ends of the conductor 631 are exposed from the insulating tube 632, one end of which is electrically connected to the positive electrode connection terminal 62, and the other end of which is electrically connected to the response voltage signal output means 521 via point c (see Figure 3(b)). This electrically connects the first proximity portion 12a of the positive electrode tab 12 to the response voltage signal output means 521, allowing electrical signals from the positive electrode tab 12 to be input to the response voltage signal output means 521 via the positive electrode connection terminal 62 and the positive electrode wiring 63. Furthermore, since the conductor 631 is insulated from the first magnetic shield 40 by the insulating tube 632, electrical signals can be transmitted in an insulated state from the first magnetic shield 40.

[0031] As shown in Figure 4(a), in the negative electrode recess 612, a portion of the negative electrode connection terminal 64, made of conductive material, is embedded in the connection terminal holding member 61. As shown in Figure 4(b), the negative electrode connection terminal 64 is made of a substantially U-shaped conductive material, and the negative electrode tab 13 is press-fitted into this U-shaped groove, thereby making contact with the negative electrode tab 13 and establishing an electrical connection. This negative electrode connection terminal 64 is electrically connected to the negative electrode tab 13 in the region near point b of the second proximity portion 13a. The second proximity portion 13a is the portion of the negative electrode tab 13 that is close to the positive electrode tab 12, and in this embodiment, it is the portion adjacent to the positive electrode tab 12 of the same battery cell. The distance D between points a and b is not particularly limited, but can be 10 cm to 30 cm.

[0032] One end of the negative electrode wiring 65 is connected to this negative electrode connection terminal 64. Like the positive electrode wiring 63, this negative electrode wiring 65 also passes through the first magnetic shield 40, and its other end is electrically connected to the response voltage signal output means 521 via point d (see Figure 3(b)).

[0033] Furthermore, the negative electrode wiring 65, like the positive electrode wiring 63, includes a conductive conductor 651 and an insulating tube 652 covering the conductor 651, and the second proximity portion 13a of the negative electrode tab 13 and the response voltage signal output means 521 are electrically connected by the conductor 651. With this configuration, the response voltage signal output means 521 can detect the voltage between the first and second proximity portions 12a and 13a. By using the response voltage signal connection means 60 described above, the assembly of the battery module 1A becomes easier.

[0034] By detecting the response voltage between the first and second proximity sections 12a and 13a in this manner, the closed-circuit area Si of the signal line used to detect the response voltage can be minimized, as shown in Figure 4(c). Since the noise signal level is proportional to the product of the closed-circuit area Si and the intersecting magnetic flux density that causes noise, the noise signal level can be reduced by reducing the closed-circuit area Si. The positive electrode wiring 63 and the negative electrode wiring 65 may be twisted-pair cables that are twisted together. By having the positive and negative electrode wirings 63 and 65 as twisted-pair cables, electromagnetic induction noise from the positive and negative electrode wirings 63 and 65 can be canceled out by each other.

[0035] Returning to Figure 3(b), the cell current signal output means 522 detects the current flowing through the battery cell 10a when an AC signal is applied to the battery module 1A, and outputs a current signal indicating the current to the cell state diagnostic means 523. Figure 5 is an explanatory diagram showing an example of a method for detecting the current flowing through the battery cell 10a in the first embodiment. In the figure, Vs represents voltage, G represents circuit gain, I represents current, and Rb represents resistance.

[0036] Since the resistance Rb between points ef shown in Figure 5 can be calculated from the material and dimensions of the intermediate busbar 22, in this embodiment, the cell current signal output means 522 detects the current I flowing through the battery cell by measuring the voltage drop between points ef in the intermediate busbar 22. As shown in Figures 3(b) and 5, the points eg and fh are connected by the current signal connection means 66. The current signal connection means 66 may be general wiring, or it may be a connection means consisting of connection terminals 62, 64 and wiring 63, 65 as shown in Figure 4(b). In this case, the current signal connection means 66 is electrically connected to the cell current signal output means 522 by passing through the first magnetic shield 40, as shown in Figure 2(b).

[0037] Furthermore, it is not necessary to detect the current flowing through the battery cells based on the voltage drop across the intermediate busbar; the current flowing through the battery cells may be detected by other methods. Also, the cell current signal output means does not necessarily need to detect the current from the battery module; for example, the current signal from a current sensor attached to the battery pack system may be acquired via wired or wireless connection and output to the cell state diagnostic means 523.

[0038] As shown in Figure 3(b), the cell state diagnostic means 523 receives a voltage signal from the response voltage signal output means 521 and a current signal from the cell current signal output means 522. In this embodiment, the cell state diagnostic means 523 diagnoses the state of the battery cell from these signals. Specifically, as described above, it calculates the electrochemical impedance of the battery cell and diagnoses the state of the battery cell. The diagnostic result is then output to an external battery pack system or the like.

[0039] Returning to Figure 2(b), the battery cells 10a and 10b are fixed inside the module cover 90 by a fixing means 80. This fixing means 80 includes a plurality of rod guides 81, a hollow rod 82, and a plurality of fixing plugs 83. The rod guides 81 are members that hold the battery cells 10a and 10b, and specifically have a holding groove 811 into which a portion of the battery cell 10a can be inserted to hold it. The rod guides 81 also have rod insertion holes 812 into which the hollow rods 82 can be inserted. These rod insertion holes 812 communicate with the rod insertion holes 71 of the spacer / support member 70, and the hollow rods 82 are inserted into the rod insertion holes 812 and 71. Fixing plugs 83 are press-fitted into the upper and lower ends of the hollow rods 82, thereby fixing the battery cells 10a and 10b held by the rod guides 81 to the module cover 90.

[0040] As shown in Figure 1, the module cover 90 includes a front cover 91, an upper cover 92, and a lower cover 93. The front cover 91 covers the battery cells 10a and 10b from the front side so that the external terminals 30 are exposed to the outside. The upper cover 92 and the lower cover 93 each cover the battery cells 10a and 10b from the main surface (upper and lower surfaces in this embodiment) side of the battery cells 10a and 10b, and have parallel surfaces that are substantially parallel to the main surface of the battery cells 10a and 10b.

[0041] This module cover 90 constitutes a second magnetic shield by being made of a magnetic material, similar to the first magnetic shield 40. The magnetic material constituting the module cover 90 may be the same material as the first magnetic shield 40, or it may be a different material.

[0042] The module cover 90 acts as a second magnetic shield, which allows it to absorb electromagnetic noise induced in the cell status monitoring circuit 52 from connection lines (busbars) to adjacent battery modules, other high-voltage relays within the battery pack, and electrical units. Furthermore, it can similarly absorb magnetic flux within the module cover 90, thereby reducing bidirectional magnetic flux transmission.

[0043] Figure 6(a) is an explanatory diagram illustrating the magnetic field generated around the battery cell in the first embodiment, and Figure 6(b) is an explanatory diagram illustrating the shielding effect by the first magnetic shield in the first embodiment. As shown in Figure 6(a), the measured current I s While current flows through the battery cell, a magnetic field is generated around the battery cell, but the measured current I of the positive and negative electrode tabs 12 and 13 s Since the directions of flow are opposite to each other, the magnetic flux φ in the close space between the positive and negative pole tabs 12 and 13 s The magnetic flux density doubles (adds up), and the noise effect on the cell state monitoring circuit board 50 increases. In contrast, in the case of the battery module 1A in this embodiment, as shown in Figure 6(b), the positive and negative electrode tabs 12, 13 and the busbar 20 are covered by the first magnetic shield 40, so the magnetic flux φ of both polesp ,φ n These cancel each other out inside the shield. As a result, the combined effect of the magnetization effect of the first magnetic shield 40 (drawing magnetic flux into the magnetic shield) and the cancellation (differential) of the absorbed magnetic flux causes the magnetic flux (leakage flux) φ to leak out from the first magnetic shield 40 to the outside. l This can reduce electromagnetic induction noise. Therefore, even if the cell condition monitoring circuit board 50 is mounted near the strong magnetic field region around the positive and negative electrode tabs 12, 13 and the busbar 20, the influence of electromagnetic induction noise can be reduced. As a result, the use of wiring materials can be minimized to reduce costs, while miniaturization and precise condition diagnosis can be achieved by reducing electromagnetic induction noise caused by cell current.

[0044] In the above embodiment, a spacer and support member 70 is interposed between the battery cells 10a and 10b, but a cell status monitoring circuit board 50 may be used as this spacer and support member. This first modified example will be described with reference to Figure 7. Figure 7 is a front view showing an example of a battery module in the first modified example.

[0045] In this first modified battery module 1B, a cell status monitoring circuit board 50 is provided instead of a spacer / support member 70, and two cell status monitoring circuit boards 50 are interposed between the battery cells 10a and 10b. With such a battery module 1B, cost reduction due to a reduction in the number of parts, weight reduction, ease of assembly (productivity), and improved space efficiency can be achieved, thereby increasing the energy density of the battery pack.

[0046] In this case, the cell status monitoring circuit board 50 can be manufactured using a glass epoxy printed circuit board manufacturing method. Alternatively, the cell status monitoring circuit board 50 may be manufactured by directly forming a circuit pattern on a resin-molded substrate using inkjet printing or the like. Or, the cell status monitoring circuit board 50 may be manufactured by forming a circuit on a flexible substrate and then joining it to a resin-molded spacer / cell support member. Furthermore, a heat dissipation line for the operating heat of the electronic components can be added to the cell status monitoring circuit board 50, and the heat can be dissipated to the module cover via the fixing means 80. This configuration is also advantageous in promoting heat dissipation of the discharge resistor when the cell balancing function built into the cell status monitoring circuit board 50 is in operation.

[0047] Furthermore, in the first embodiment described above, the battery module 1A contained two battery cells, but the number of battery cells is not limited to this, and may contain three or more battery cells. The number of battery cells can be appropriately selected depending on the application of the battery cells and the conditions of the mounting location. Here, a second modified example having four battery cells will be described with reference to the figures. Figure 8(a) is a front view showing an example of a battery module in the second modified example, and Figure 8(b) is a circuit diagram showing an example of the battery module. Note that in Figure 8(a), for convenience, the busbars and external terminals are omitted from the illustration, and the electrical connection relationships will be explained using the circuit diagram in Figure 8(b).

[0048] As shown in Figures 8(a) and 8(b), in the battery module 1C of the second modified example, a cell set consisting of parallel-connected battery cells 10c and 10d is connected in series with a cell set consisting of parallel-connected battery cells 10e and 10f. Furthermore, as shown in Figure 8(a), the two cell sets connected in series are stacked with their front and back sides reversed, which simplifies the folding connection of the busbars and enables high-density mounting.

[0049] In the second modified example, multiple (four in this example) cell status monitoring circuit boards 50 are used as both spacers and support members. Each cell status monitoring circuit board 50 detects the response voltage for each battery cell 10c to 10f and monitors the status of the battery cells. This configuration, which allows for monitoring the status of each battery cell, can be universally applied to various applications. Therefore, a battery module 1C with this configuration enables mass production of a limited number of product types, simplifying production equipment and reducing production costs.

[0050] It is not necessarily required to provide a cell status monitoring circuit board 50 for each battery cell; for example, a cell status monitoring circuit board 50 may be provided for each cell set. This third modified example will be explained with reference to Figure 9. Figure 9(a) is a front view showing an example of a battery module in the third modified example, and Figure 9(b) is a circuit diagram showing an example of the battery module. For convenience, the busbars and external terminals are not shown in Figure 9(a), and the electrical connection relationships will be explained using the circuit diagram in Figure 9(b).

[0051] As shown in Figures 9(a) and 9(b), in the third modified example, the battery module 1D has, similar to the second modified example, a cell set consisting of parallel-connected battery cells 10c and 10d and a cell set consisting of parallel-connected battery cells 10e and 10f connected in series. The response voltage signal connection means 60 is connected to the positive and negative electrode tabs 12 and 13 of the battery cell 10d and the positive and negative electrode tabs 12 and 13 of the battery cell 10f, and the cell status monitoring circuit board 50 detects the response voltages of the battery cells 10d and 10f.

[0052] Since the cell voltages of battery cells connected in parallel are common, the cell status monitoring circuit board 50 can be consolidated and provided for each cell set. This reduces the number of cell status monitoring circuit boards 50, thus reducing costs. If necessary, the current flowing through each battery cell connected in parallel may be detected and input to the cell status monitoring circuit board 50. In this case, the impedance of each battery cell connected in parallel can be determined separately. Thus, in the second embodiment as in the first embodiment, electromagnetic induction noise can be reduced and precise status diagnosis can be achieved.

[0053] ≪Second Embodiment≫ Next, a second embodiment of the battery module according to the present invention will be described with reference to Figure 10. In the following description, parts that have the same configuration as in the first embodiment will be denoted by the same reference numerals and their description will be omitted. Figure 10(a) is a plan view showing an example of the battery module 1E in the second embodiment, and Figure 10(b) is a front view showing an example of the battery module.

[0054] As shown in Figure 10(a), the battery module 1E in the second embodiment is a double-sided output terminal type cell, and differs from the first embodiment in that the positive and negative electrode tabs 12 and 13 of the battery cells 10g to 10j do not extend from the same side. The positive electrode tab 12 of the battery cells 10g to 10j extends from one side of the battery cells 10g to 10j, and the negative electrode tab 13 extends from the other side opposite to the side from which the positive electrode tab 12 extends.

[0055] Furthermore, in the battery cells 10g to 10j, the positive electrode tabs 12 are arranged so that they are adjacent to the negative electrode tabs 13 of other battery cells, and these adjacent positive and negative electrode tabs 12 and 13 are covered by the first magnetic shield 40. In addition, the adjacent positive and negative electrode tabs 12 and 13 are connected by a cell connection busbar 24, and a portion of this cell connection busbar 24 is also covered by the first magnetic shield 40.

[0056] A cell state monitoring circuit board 50 is provided on the first magnetic shield 40, similar to the first embodiment. The response voltage signal output means 521 (see Figure 3(b)) of this cell state monitoring circuit board 50 is electrically connected to the first proximity portion 12a of the positive electrode tab 12, and also to the second proximity portion 13a of the negative electrode tab 13, similar to the first embodiment. Furthermore, the cell current signal output means 522 of this cell state monitoring circuit board 50 is electrically connected to the busbar by a current signal connection means 66, similar to the first embodiment.

[0057] In the battery module 1E of the second embodiment, a cell status monitoring circuit board 50 is provided with two battery cells connected in series as a pair. Therefore, the measured impedance is the sum of the internal impedance of the two cells and the impedance of the cell connection busbar 24 and the positive and negative electrode tabs 12 and 13. Consequently, it does not provide a status diagnosis for each individual battery cell, but this is not a problem as long as the pair of battery cells are used without being separated.

[0058] ≪Third Embodiment≫ Next, a third embodiment of the battery module according to the present invention will be described with reference to the drawings. In the following description, parts that have the same configuration as those in the first and second embodiments will be denoted by the same reference numerals and their description will be omitted.

[0059] Figure 11 is an exploded perspective view showing an example of a battery module 1F in the third embodiment. Figure 12 is a circuit diagram showing an example of a cell state monitoring circuit 52B in the third embodiment. Figure 13(a) is a front view showing an example of a cell state monitoring circuit board 50B in the third embodiment. Figure 14 is an exploded cross-sectional view showing an example of a battery module 1F in the third embodiment.

[0060] As shown in Figure 11, this third embodiment differs from the first and second embodiments mainly in the configuration of the cell state monitoring circuit board 50B. Furthermore, the battery module 1F differs from the first and second embodiments in that it has two stages of positive terminals 31, two stages of intermediate terminals 32, and two stages of negative terminals 33.

[0061] As shown in Figure 11, the module portion 100 of the battery module 1F includes a positive terminal 31, an intermediate terminal 32, and a negative terminal 33, all of which are exposed to the outside of the module cover 90. The positive terminal 31 includes an upper positive terminal 31a and a lower positive terminal 31b, and the intermediate terminal 32 includes an upper intermediate terminal 32a and a lower intermediate terminal 32b. The negative terminal 31 includes an upper negative terminal 33a and a lower negative terminal 33b.

[0062] In this module section 100, the upper and lower positive terminals 31a, 31b and the upper and lower negative terminals 33a, 33b are arranged in a square shape with these terminals as corners. In this square, the upper positive terminal 31a is positioned diagonally to the lower positive terminal 31b, and the upper negative terminal 33a is positioned diagonally to the lower negative terminal 33b.

[0063] Furthermore, the upper positive terminal 31a and the upper negative terminal 33a are arranged horizontally with a gap between them, and the lower positive terminal 31b and the lower negative terminal 33b are also arranged horizontally with a gap between them. On the other hand, the upper positive terminal 31a and the lower negative terminal 33b are arranged vertically with a gap between them, and the upper negative terminal 33a and the lower positive terminal 31b are also arranged vertically with a gap between them.

[0064] As shown in Figure 12, in the module 100 of this embodiment, four battery cells 10k to 10n are connected in two stages of four in series. The cell status of the battery cells 10k to 10n is diagnosed based on the voltage between the terminals (cell voltage) detected by the response voltage signal output means 521 and the AC current value detected by the cell current signal output means 522.

[0065] As shown in Figures 11 to 13(a), the positive terminal 31, intermediate terminal 32, and negative terminal 33 of this module 100 are connected to the cell status monitoring circuit board 50B. The cell status monitoring circuit board 50B further includes a measurement current input connector 524, a positive terminal connection part 525, an intermediate connection part 526, a negative terminal connection part 527, an insulating guide 53, a cover 54, and a plurality (two in this example) of first magnetic shields 40B1, 40B2 (see Figure 13(a)).

[0066] The measurement current input / output connector 524 is electrically connected to an external power supply (not shown). An AC signal (measurement current) is supplied to the cell status monitoring circuit board 50B and the battery cell via this measurement current input / output connector 524.

[0067] As shown in Figures 11 and 12, the positive electrode connection portion 525 is made of a conductive material such as metal and is the part that connects to the positive electrode terminal 31. This positive electrode connection portion 525 has an upper positive electrode connection portion 525a and a lower positive electrode connection portion 525b, corresponding to the positive electrode terminal 31 of the module portion 100.

[0068] As shown in Figure 11, the upper positive electrode connection portion 525a in this embodiment is composed of a pair of metal plates. The upper positive electrode connection portion 525a is the part that contacts and electrically connects with the upper positive electrode terminal 31a. As shown in Figure 14, the upper positive electrode connection portion 525a in this embodiment has a screw hole, and is connected to the upper positive electrode terminal 31a by fastening this screw hole with a bolt B.

[0069] As shown in Figure 11, the lower positive electrode connection portion 525a is also composed of a pair of metal plates. The lower positive electrode connection portion 525b is the part that contacts and electrically connects with the lower positive electrode terminal 31b. In this embodiment, the lower positive electrode connection portion 525b also has a screw hole, and is connected to the lower positive electrode terminal 31b by fastening this screw hole with a bolt B.

[0070] The intermediate connection section 526 is made of a conductive material such as metal and is the part that connects to the intermediate terminal 32. In this embodiment, the battery module 1F has an upper intermediate terminal 32a and a lower intermediate terminal 32b as intermediate terminals 32, and the intermediate connection section 526 also has an upper intermediate connection section 526a and a lower intermediate connection section 526b corresponding to these. The upper intermediate connection section 526a is connected to the upper intermediate terminal 32a by bolt B, and the lower intermediate connection section 526b is connected to the lower intermediate terminal 32b by bolt B. No current is conducted through this intermediate terminal 32.

[0071] The negative electrode connection portion 527 is made of a conductive material such as metal and is the part that connects to the negative electrode terminal 33. The negative electrode connection portion 527 also has an upper negative electrode connection portion 527a and a lower negative electrode connection portion 527b, corresponding to the negative electrode terminal 33.

[0072] As shown in Figure 11, the upper negative electrode connection portion 527a in this embodiment is also composed of a pair of metal plates. The upper negative electrode connection portion 527a is the part that contacts and electrically connects with the upper negative electrode terminal 33a. The upper negative electrode connection portion 527a is also connected to the upper negative electrode terminal 33a by bolt B. Furthermore, as shown in Figures 12 and 13(a), the upper negative electrode connection portion 527a is connected to the lower positive electrode connection portion 527b by an external busbar 528.

[0073] As shown in Figure 11, the lower negative electrode connection portion 527b is also composed of a pair of metal plates. The lower negative electrode connection portion 527b is the part that contacts and electrically connects with the lower negative electrode terminal 33b. The lower negative electrode connection portion 527b is also connected to the lower negative electrode terminal 33b by bolt B.

[0074] As shown in Figure 12, the upper positive terminal connector 525a is electrically connected to the measurement current input / output connector 524, and an AC signal (measurement current) is supplied from an external power supply (not shown) via the measurement current input / output connector 524. The measurement current then flows through the upper positive terminal 31a, battery cells 10k and 10l, upper negative terminal 33a, upper negative terminal connector 527a, external busbar 528, lower positive terminal connector 525a, lower positive terminal 31b, battery cells 10m and 10n, lower negative terminal 33b, lower negative terminal connector 527b, and the measurement current input / output connector 524 in this order.

[0075] As shown in Figure 11, the insulating guide 53 is provided on the base material 51. The insulating guide 53 is not particularly limited, but is made of a resin mixed with powdered magnetic material, so that the entire insulating guide 53 is a magnetic material with a magnetic shielding effect. As the powdered magnetic material, for example, metal powder or ceramic powder such as ferrite can be used. As the resin, for example, ABS resin can be used.

[0076] The insulating guide 53 is positioned to surround the positive electrode connection portion 525, the intermediate connection portion 526, and the negative electrode connection portion 527 described above. This insulating guide 53 has a guide portion 531 at a position corresponding to the connection portions 525 to 527. As shown in Figure 14, this guide portion 531 is a through hole and positions the terminals 31 to 33 relative to the connection portions 525 to 527 when connecting the terminals 31 to 33 to the connection portions 525 to 527.

[0077] Such insulating guides 53 can shield not only the magnetic flux from the connection points 525-527 and terminals 31-33, but also the electromagnetic interference between circuits implemented in the cell state monitoring circuit 52, such as the current measurement circuit (cell current signal output means 522). As a result, the voltage between the positive and negative electrodes of the cell is detected more accurately (the signal-to-noise ratio is improved), and the impedance measurement accuracy is improved.

[0078] Furthermore, because the insulating guide 53 contains resin, the insulating guide 53 has high electrical impedance (electrical resistance). Even if the terminals 31-33 and the guide portion 531 of the insulating guide 53 come into contact during installation, a short circuit severe enough to cause damage to the battery cell can be prevented. Additionally, since the connection portions 525-527 are located at the bottom of a recessed area the thickness of the insulating guide, even if a conductive object comes into contact with the energized cell status monitoring circuit board 50B, the insulating guide 53 functions as a bumper, preventing a short circuit between the object and the connection portions 525-527. This allows for safe and rapid impedance measurement, shortening the time required for the cell status diagnosis process and reducing the cost of remanufacturing used battery cells for secondary use.

[0079] The cover 54 is a plate-shaped magnetic material that covers the front and back surfaces (see Figure 14) of the base material 51. For example, an iron plate can be used as this magnetic material. Alternatively, a thin film of magnetic material can be attached to the surface of a resin. Furthermore, if the measurement current is high frequency, non-ferrous metals such as aluminum can also be used as they can provide a shielding effect. The cover 54 has openings 541 at positions corresponding to the connection parts 525 to 527 and the measurement current input / output connector 524.

[0080] The cover 54 prevents external electromagnetic waves, including magnetic flux generated by the measurement current, from interfering with the cell state monitoring circuit 52 and superimposing induced electromotive force onto the detection signal. As a result, even if the module cover 90 is made of a material that does not have a magnetic shielding effect, such as resin, the magnetic flux generated from the battery cell by the measurement current is magnetized by the cover 54, and by circulating through the cover 54, the magnetic flux interfering with the cell state monitoring circuit 52 can be reduced. Therefore, the voltage between the positive and negative electrodes of the cell can be accurately detected, improving the accuracy of impedance measurement. Furthermore, since a magnetic shielding effect against electromagnetic waves can be provided even in manufacturing plants and maintenance facilities where various electromagnetic interferences are possible, the cell state can be diagnosed even without a special inspection room with magnetic shielding.

[0081] The first magnetic shields 40B1 and 40B2 shown in Fig. 13(a) include a magnetic layer formed of at least a magnetic material, similarly to the first and second embodiments described above. In the present embodiment, the first magnetic shields 40B1 and 40B2 are embedded in an insulating guide 53.

[0082] The first magnetic shield 40B1 is disposed so as to cover the upper positive electrode connection portion 525a and the lower negative electrode connection portion 527b. Therefore, the first magnetic shield 40B1 covers the periphery of the upper positive electrode terminal 31a and the lower negative electrode terminal 33b in a state where the cell state monitoring circuit board 50B is mounted to the module portion 100.

[0083] In this manner, by covering the combination of the upper positive electrode terminal 31a and the lower negative electrode terminal 33b, and the combination of the upper positive electrode connection portion 525a and the lower negative electrode connection portion 527b with the first magnetic shield 40B1 along the conduction direction of the measurement current, magnetic flux generated by the measurement current is attracted into the first magnetic shield 40B1 and circulates therein.

[0084] The magnetic flux φ circulating in the first magnetic shield 40B1 PU , φ NL are both generated from a common measurement current, so the polarities of the magnetic flux φ PU , φ NL are opposite to each other and have the same absolute value. For this reason, the magnetic flux φ PU and the magnetic flux φ NL cancel each other out within the first magnetic shield 40B1. This magnetic flux canceling effect can reduce leakage magnetic flux φ l that leaks out of the first magnetic shield 40B1. As a result, induced electromotive force generated when magnetic flux intersects with the cell state diagnostic means 523 and the like mounted outside the first magnetic shield 40B1 is reduced. Consequently, the voltage between the positive electrode and negative electrode of the cell can be detected more accurately, thereby improving impedance measurement accuracy.

[0085] Furthermore, since the first magnetic shield 40B1 covers the upper positive electrode connection part 525a and the lower negative electrode connection part 527b, which are located in close proximity to each other, the first magnetic shield 40B1 can be miniaturized, thereby improving the efficiency of material use. Also, as described above, leakage flux φ l By reducing the size of the battery cell, the cell state monitoring circuit 52 can be mounted near the upper positive electrode connection 525a and the lower negative electrode connection 527b, thereby allowing the cell state monitoring circuit board 50B to be miniaturized. As a result, the cost of the battery cell state diagnostic device, such as the SOH (state of health), can be reduced, and the measurement accuracy can be improved.

[0086] On the other hand, the first magnetic shield 40B2 is positioned to surround the upper negative electrode connection portion 527a and the lower positive electrode connection portion 525b. Therefore, when the cell state monitoring circuit board 50B is mounted on the module portion 100, the first magnetic shield 40B2 covers the upper negative electrode terminal 33a and the lower positive electrode terminal 31b. Similar to the first magnetic shield 40B1, this first magnetic shield 40B2 also contributes to cost reduction and improved measurement accuracy.

[0087] The first magnetic shield only needs to be able to cover the combination of the positive terminal 31 and the negative terminal 33 by covering the combination of the positive terminal connection part 525 and the negative terminal connection part 527, and does not need to be in the shape described above. Specific modifications will be explained with reference to Figures 13(b) and 13(c).

[0088] Figure 13(b) is a front view showing an example of a cell state monitoring circuit board 50C in the fourth modified example. In the cell state monitoring circuit board 50C shown in Figure 13(b), the first magnetic shield 40C1 covers the combination of upper positive electrode connection portion 525a and upper negative electrode connection portion 527a arranged horizontally. Similarly, the first magnetic shield 40C2 covers the combination of lower positive electrode connection portion 525b and lower negative electrode connection portion 527b arranged horizontally.

[0089] In this case as well, since the first magnetic shields 40C1 and 40C2 cover terminals 31 and 33 and connection parts 525 and 527 with different polarities, the magnetic fluxes cancel each other out inside the first magnetic shields 40C1 and 40C2. Therefore, measurement accuracy can be improved. Also, for example, when measuring battery cells in upper and lower stages (when you want to measure only the cells in one stage), you can select a module to which the measurement current flows.

[0090] Figure 13(c) is a front view showing an example of a cell state monitoring circuit board 50D in the fifth modified example. In the cell state monitoring circuit board 50D shown in Figure 13(c), a first magnetic shield 40D covers all of the positive electrode connection portions 525 and negative electrode connection portions 527.

[0091] Even in this case, since the first magnetic shield 40D covers terminals 31, 33 and connection parts 525, 527 of different polarities, the magnetic fluxes cancel each other out inside the first magnetic shield 40D. Therefore, measurement accuracy can be improved. Furthermore, by arranging only one first magnetic shield 40D, even when the distance between electrodes is small, such as in a small battery module, a thick first magnetic shield 40D can be used, and the processing size of the first magnetic shield 40D does not become too small, thus suppressing an increase in manufacturing costs.

[0092] Figure 15(a) is a front view showing an example of a cell state monitoring circuit board 50E in the sixth modified example. As shown in Figure 15(a), the first magnetic shield 40E may have a cylindrical portion 401 and a pair of partition walls 402a, 402b that divide the internal space of the cylindrical portion 401 into three areas.

[0093] Partition wall 402a, together with a portion of the cylindrical portion 401, is positioned to surround the upper positive electrode connection portion 525a and the upper positive electrode terminal 31a. On the other hand, partition wall 402b, together with a portion of the cylindrical portion 401, is positioned to surround the upper negative electrode connection portion 527a and the upper negative electrode terminal 33a. Although not specifically shown in the figures, a first magnetic shield 40E is also provided on the cell state monitoring circuit board 50E, surrounding the lower positive electrode connection portion 525b and the lower negative electrode connection portion 527b.

[0094] As described above, the magnetic flux φ generated by the measurement current PU ,φ NU Although the first magnetic shield 40E is magnetized by the cylindrical portion 401, the leakage magnetic flux φ pl ,φ nl In some cases, leakage magnetic flux φ may occur inside the cylindrical part 401. The signal line 529 of the cell state monitoring circuit 52B and the leakage magnetic flux φ pl ,φ nl As the circuit area S where these two circuits intersect becomes larger, an induced electromotive force is superimposed on the detection signal, causing measurement errors.

[0095] In contrast, in this sixth modified example, the leakage flux φ is controlled by the partitions 402a and 402b. pl ,φ nl By magnetizing it, the leakage magnetic flux φ pl ,φ nl This reduces the circuit area S where the circuits intersect. This, in turn, improves the accuracy of impedance measurement.

[0096] Figure 15(b) is a front view showing an example of a cell state monitoring circuit board 50F in the seventh modification. In this seventh modification, a response voltage signal output means 521 (differential amplifier) ​​is arranged between a pair of partition walls 402a and 402b of the first magnetic shield 40F. The insulating guide 53 in this modification is machined to create a space between it and the base material 51 to accommodate the differential amplifier. Although not specifically shown, the cell state monitoring circuit board 50F also has a first magnetic shield 40F surrounding the lower positive electrode connection portion 525b and the lower negative electrode connection portion 527b.

[0097] A differential amplifier is an important device for improving the accuracy of impedance measurement. It is used to remove the DC voltage (common voltage, e.g., 4V) of a battery pack, which is extremely large compared to the AC voltage signal to be detected (e.g., 1mV). Its input impedance is high, around 1MΩ. Therefore, it has the characteristic of easily picking up external electromagnetic waves, including induced electromotive force. For this reason, it is desirable to place the differential amplifier as close as possible to the measurement point. In this modified example, the differential amplifier is mounted near the upper positive and negative electrode connection sections 525a, 527a (and the upper positive and negative electrode terminals 31a, 33a). However, the area near the upper positive and negative electrode connection sections 525a, 527a is susceptible to magnetic flux (leakage flux φ) generated by the measurement current. pl ,φ nl Because of the presence of this magnetic flux, there is a risk that the detection accuracy will decrease. In contrast, in the seventh modified example, the leakage magnetic flux φ is reduced by the partitions 402a and 402b. pl ,φ nl By using magnetization, the impact on the differential amplifier can be reduced, thereby improving the accuracy of impedance measurement.

[0098] Figure 15(c) is a front view showing an example of a cell state monitoring circuit board 50G in the eighth modified example. In this eighth modified example, the first magnetic shield 40G covering all positive electrode connections 525 and negative electrode connections 527 has partitions 402a and 402b. These partitions 402a and 402b shield all positive electrode connections 525 and negative electrode connections 527 from the four differential amplifiers 521. In this eighth modified example as well, the influence of leakage flux on the differential amplifiers 521 can be reduced, thereby improving the accuracy of impedance measurement.

[0099] While embodiments of the present invention have been described above, these embodiments are provided to facilitate understanding of the present invention and are not intended to limit it. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0100] 1A~1F...Battery Module 10A~10J...Battery cell 12…Positive electrode tab 12a...First proximity section 13... Negative electrode tab 13a...Second proximity section 30…External terminals 31…Positive terminal 31a... Upper positive terminal 31b…lower positive terminal 32…Intermediate terminal 32a... Upper intermediate terminal 32b…Lower intermediate terminal 33...Negative terminal 33a...Upper negative terminal 33b…lower negative terminal 40, 40B1~40G...First magnetic shield 401...Cylindrical part 402…Bulkhead 50, 50B~50F...Cell status monitoring circuit board 52, 52B... Cell status monitoring circuit 521...Response voltage signal output means 522... Cell current signal output means 523... Cell status diagnostic means 53…Insulation Guide 531... Guide Section 60...Response voltage signal connection means 66...Means for connecting current signals

Claims

1. A battery module comprising multiple battery cells, a positive electrode, and a negative electrode, A cylindrical first magnetic shield covering the positive electrode and the negative electrode, The system includes a cell status monitoring circuit located outside the first magnetic shield, which monitors the state of the battery cell, The aforementioned cell status monitoring circuit is A response voltage signal output means that outputs a voltage signal indicating the voltage between the positive electrode and the negative electrode, A cell current signal output means that outputs a current signal indicating the current flowing through the battery cell, The system includes a cell state diagnostic means that diagnoses the state of the battery cell based on the voltage signal output from the response voltage signal output means and the current signal output from the cell current signal output means, The positive electrode includes the positive electrode tab of the battery cell, The negative electrode includes the negative electrode tab of the battery cell, The first magnetic shield covers the positive electrode tab and the negative electrode tab. The battery module is electrically insulated from the first magnetic shield and further comprises a response voltage signal connection means that penetrates the first magnetic shield and electrically connects a first proximity portion of the positive electrode tab adjacent to the negative electrode tab with the cell state monitoring circuit, and electrically connects a second proximity portion of the negative electrode tab adjacent to the positive electrode tab with the cell state monitoring circuit. The response voltage signal output means is electrically connected to the response voltage signal connection means and outputs a voltage signal indicating the voltage between the first and second proximity parts. The cell state monitoring circuit is located in the vicinity of the response voltage signal connection means within the battery module.

2. A battery module according to claim 1, The positive electrode tab and the negative electrode tab extend from the same side of the battery cell so as to be adjacent to each other. The first magnetic shield is a battery module that covers the positive electrode tab and the negative electrode tab extending from the same side of the battery cell.

3. A battery module according to claim 1, The positive electrode tab extends from one side of the battery cell, The negative electrode tab extends from the other side opposite to the side from which the positive electrode tab extends. The plurality of battery cells are arranged such that the positive electrode tabs are adjacent to the negative electrodes of other battery cells. The first magnetic shield is a battery module that covers the adjacent positive electrode tab and the negative electrode tab.

4. A battery module according to claim 1, The aforementioned positive electrode is, The positive electrode tab of the aforementioned battery cell, The positive electrode tab and the positive electrode terminal are electrically connected, The aforementioned negative electrode is The negative electrode tab of the aforementioned battery cell, The negative electrode tab and the negative electrode terminal are electrically connected, The first magnetic shield is a battery module that covers the positive terminal and the negative terminal.

5. A battery module according to claim 4, The positive terminal and the negative terminal are arranged in a battery module with a gap between them along the vertical direction.

6. A battery module according to claim 4, The battery module is arranged so that the positive terminal and the negative terminal are spaced apart from each other along the horizontal direction.

7. A battery module according to claim 4, The aforementioned positive terminal is Lower positive terminal and It includes an upper positive terminal that is positioned diagonally opposite to the lower positive terminal and is positioned relatively above the lower positive terminal, The aforementioned negative terminal is Lower negative terminal and It includes an upper negative terminal that is positioned diagonally opposite to the lower negative terminal and is positioned relatively above the lower negative terminal, The upper positive terminal is positioned above the lower negative terminal. The aforementioned upper negative terminal is positioned above the aforementioned lower positive terminal. The battery module is equipped with a plurality of the first magnetic shields, The first magnetic shield covers the upper positive terminal, the lower positive terminal, the upper negative terminal, and the lower negative terminal of the battery module.

8. A battery module according to claim 4, The first magnetic shield is, A cylindrical portion that houses the positive terminal and the negative terminal inside, A battery module having a partition wall positioned between the positive terminal and the negative terminal inside the cylindrical portion.

9. A battery module according to claim 8, The response voltage signal output means is a battery module located in the internal space enclosed by the cylindrical portion and the partition wall.

10. A battery module according to claim 4, The aforementioned cell status monitoring circuit is A positive terminal connection part that connects to the positive terminal, A negative electrode connection part that connects to the aforementioned negative electrode terminal, It has a guide section, The battery module includes a guide portion which positions the positive electrode terminal relative to the positive electrode connection portion when connecting the positive electrode terminal to the positive electrode connection portion, and positions the negative electrode terminal relative to the negative electrode connection portion when connecting the negative electrode terminal to the negative electrode connection portion.

11. A battery module according to claim 1, The aforementioned battery module is The system further comprises a spacer and support member interposed between the plurality of battery cells and supporting the battery cells, The spacer and support member is a battery module, which is a printed circuit board on which the cell status monitoring circuit is mounted.

12. A battery module according to claim 1, The battery module further comprises a module cover that houses the battery cells and the cell status monitoring circuit inside, The module cover comprises a battery module having a second magnetic shield with a parallel surface substantially parallel to the battery cell, the positive electrode tab, and the negative electrode tab.

13. A battery module according to claim 1, The battery module includes a plurality of cell status monitoring circuits provided for each of the battery cells, Multiple of the aforementioned cell status monitoring circuits are stacked on top of each other in a battery module.

14. A battery module according to claim 1, The aforementioned battery module is A cell set consisting of the plurality of battery cells connected in parallel via a busbar, A battery module comprising a plurality of cell status monitoring circuits provided for each of the aforementioned cell sets.

15. A battery module according to claim 1, The response voltage signal connection means is A connection terminal holding member made of insulating material, which can be fitted between the positive electrode tab and the negative electrode tab, A positive electrode connection terminal, made of a conductive material and embedded in the connection terminal holding member, electrically connects the first proximity portion of the positive electrode tab and the response voltage signal output means by press-fitting the positive electrode tab into contact with it, A battery module having a negative electrode connection terminal made of a conductive material, embedded in the connection terminal holding member, and electrically connecting the second proximity portion of the negative electrode tab and the response voltage signal output means by press-fitting the negative electrode tab into it and bringing it into contact.

16. A battery module according to claim 1, The cell state diagnostic means has a function to calculate the electrochemical impedance of the battery cell, A battery module in which the measurement frequency of the electrochemical impedance is 100 kHz or less.

17. A battery module according to claim 1, The battery module further comprises an insulator interposed between the first magnetic shield and the cell state monitoring circuit.

18. A battery module according to any one of claims 1 to 17, The first magnetic shield is a battery module made of a soft magnetic material.

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