Battery module

Abstract

To solve a problem in which conventional battery modules cannot be used in battery modules that stack battery cells, which repeatedly expand and contract with charging and discharging.SOLUTION: A battery module M includes a battery stack S in which battery cells C are stacked, a voltage detection circuit 1 which detects a terminal voltage of the battery cells C, and a detection wire bundle 2 which connects the battery cell terminals T and the voltage detection circuit 1, and the battery stack S is displaceable with one end in the stacking direction as a fixed end and the other end as a free end, and has a terminal row along the stacking direction, and the detection wire bundle 2 includes a body portion 3 which integrates detection wires 3A which connect to the battery cells C, and a deformation-following portion 4 which integrates detection wires 4A which connect from the body portion 3 to each battery cell C, and includes multiple combinations of the body portion 3 and the deformation-following portion 4, and maintains the function of detecting the terminal voltage of the battery cells C even when displacement occurs in the stacking direction of the battery stack S.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an improvement in a battery module having a structure in which a plurality of battery cells are stacked. [Background technology]

[0002] An example of a conventional battery module is described in Patent Document 1. Patent Document 1 describes a battery module that includes a battery block made up of multiple battery cells and a voltage detection circuit for detecting the terminal voltage of each battery cell, and that is provided with a flexible printed circuit board in the battery block for electrically connecting the positive terminal or negative terminal of the battery cell to the voltage detection circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2010-113455 A1 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional battery modules described above are not structured to accommodate displacement of the battery blocks in the stacking direction, and therefore have the problem that they cannot be used in battery modules in which battery cells that repeatedly expand and contract due to charging and discharging, such as lithium deposition-type fixed batteries, are stacked.

[0005] The present invention has been made in consideration of the above-described conventional situation, and aims to provide a battery module including a battery stack having a structure in which battery cells that repeatedly expand and contract are stacked, which can maintain the function of detecting the terminal voltage of a battery cell even if displacement occurs in the stacking direction of the battery stack. [Means for solving the problem]

[0006] The battery module according to the present invention includes a battery stack having a structure in which multiple battery cells are stacked, a voltage detection circuit that detects the voltage between the terminals of each battery cell, and a flexible detection wire band for electrically connecting the terminals of each battery cell to the voltage detection circuit. The battery stack is movable with one end fixed and the other end free in the stacking direction in response to expansion and contraction of the individual battery cells in the stacking direction due to charging and discharging, and has a terminal row in which positive and negative terminals protruding from each battery cell are arranged along the stacking direction. The battery module is characterized in that the detection wire band includes a main body portion arranged along the terminal row and integrating detection wires connected to the battery cells, and a deformation-compliant portion that integrates detection wires connected from the main body portion to the individual battery cells and deforms to follow displacement of the battery stack in the stacking direction, and includes multiple combinations of main body portion and deformation-compliant portion. [Effects of the Invention]

[0007] In the battery module of the present invention, when displacement occurs in the stacking direction of the battery stack due to expansion and contraction associated with charging and discharging of the battery cells, the deformation-following portions of each detection wire bundle band deform to follow the displacement of the battery stack, thereby maintaining the connection between the main body and each battery cell.

[0008] As a result, the battery module according to the present invention, which includes a battery stack having a structure in which battery cells that repeatedly expand and contract are stacked, can maintain its function of detecting the terminal voltage of the battery cells by following the displacement even if the battery stack is displaced in the stacking direction. Also, in the battery module described above, the detection wire bundle includes multiple main bodies and multiple deformation-following parts, so that the number of detection wires per main body can be reduced, thereby making it possible to reduce the width of the main body. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are perspective views showing expansion and contraction states of a battery module from the left to the right in a first embodiment of the battery module according to the present invention. [Figure 2] 2A and 2B are diagrams showing the battery module shown in FIG. 1, in which the upper part is a front view of the battery module when contracted with an enlarged view of the detection wire bundle band, and the lower part is a front view of the battery module when expanded. [Figure 3] FIG. 4 is a front view showing a second embodiment of a battery module according to the present invention. [Figure 4] FIG. 10 is a front view showing a third embodiment of a battery module according to the present invention. [Figure 5] FIG. 10 is a front view showing a fourth embodiment of a battery module according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment The battery module M shown in Figures 1 and 2 includes a battery stack S having a structure in which multiple battery cells C are stacked, a voltage detection circuit 1 that detects the voltage between the terminals of each battery cell C, and a flexible detection wire bundle 2 that electrically connects the terminals T of each battery cell C to the voltage detection circuit 1.

[0011] The battery module M uses battery cells C that repeatedly expand and contract due to charging and discharging, such as lithium deposition type fixed batteries. Therefore, when the battery stack S is charged in the initial state shown on the right side of Fig. 1, the battery stack S expands overall in the stacking direction due to the expansion of each battery cell C, as shown on the left side of Fig. 1.

[0012] Therefore, the above-mentioned battery module M is housed in a case 50 having a structure capable of following the displacement of the battery stack S, and the side of the case 50 has a terminal row in which positive or negative terminals (tabs) T protruding from each battery cell C are arranged, and a voltage detection circuit 1 is fixed to the end face of the case 50, and a detection wire bundle band 2 is arranged on the side where the terminal row appears.

[0013] The battery stack S is movable in response to expansion and contraction in the stacking direction due to charging and discharging of the individual battery cells C, with one end in the stacking direction (the end opposite the voltage detection circuit 1) as a fixed end and the other end as a free end, and has the above-mentioned terminal row along the stacking direction.

[0014] The detection wire bundle band 2 is a film-shaped flexible printed circuit board, and as shown in the enlarged view at the top of Figure 2, it includes a main body portion 3 that integrates detection wires 3A that are arranged along the terminal row and connect to the terminals T of the battery cells C, and a deformation-following portion 4 that integrates detection wires 4A that connect from the main body portion 3 to the terminals T of individual battery cells C and that deforms to follow the displacement of the battery stack S in the stacking direction.

[0015] The battery module M includes multiple combinations of the main body portion 3 and the deformation-conforming portion 4. The battery module M of this embodiment includes two combinations of the main body portion 3 and the deformation-conforming portion 4, one on each side (top and bottom in the drawing) of the terminal row of the battery stack S.

[0016] Furthermore, the number of battery cells C in the battery module M is not limited, but as an example, a battery stack S including eight battery cells C is shown. In the detection wire bundle band 2, the upper main body portion 3 in Fig. 2 has a length equivalent to the overall length of the battery stack S in the stacking direction, and has four detection wires 3A therein, and each detection wire 3A is connected to the terminals T of the four battery cells C on the fixed end side of the battery stack S by each deformation-conforming portion 4.

[0017] 2 has a length equivalent to half the overall length of the battery stack S in the stacking direction, and like the upper body 3, has four detection lines 3A, and each detection line 3A is connected to the terminals T of the four battery cells C on the free end side of the battery stack S by a corresponding deformation-conforming portion 4. Therefore, the upper and lower body parts 3 have half the width dimension (the upper and lower width dimension in the figure) of a body that integrates eight detection lines corresponding to all battery cells C.

[0018] Each main body 3 in the detection wire bundle 2 has at least one fixed point F, and the multiple deformation-following parts 4 are configured so that the amount of deformation in the stacking direction of the battery cells C increases the farther they are from the fixed point F. Each main body 3 in the illustrated example has the fixed point F at the end on the fixed end side of the battery stack S.

[0019] Furthermore, each main body portion 3 is flexible, but does not follow the displacement of the battery stack S in the stacking direction, and therefore has a surplus portion 5 between itself and the voltage detection circuit 1, the surplus portion 5 having a length corresponding to the displacement of the battery stack S, in a bent state, as shown in an example in Figure 2. Therefore, the main body portion 3 shown in the lower part of Figure 2 includes the surplus portion 5 that is expanded linearly.

[0020] In the battery module M having the above configuration, when the battery cells C are charged in the initial state shown on the right side of Fig. 1 and in the upper part of Fig. 2, the battery stack S expands in accordance with the expansion of each battery cell C. At this time, since the battery module M has one end of the battery stack S in the stacking direction as a fixed end and the other end as a free end, as shown in the lower part of Fig. 2, the battery stack S is displaced so as to expand toward the free end.

[0021] At this time, the battery module M also increases the distance between the terminals T, T of adjacent battery cells C, but because the detection wire bundle band 2 has a structure having a main body portion 3 and a deformation-following portion 4, the deformation-following portion 4 deforms, maintaining the electrical connection between the main body portion 3 and the terminal T.

[0022] In this way, the battery module M includes a battery stack S having a structure in which battery cells C that repeatedly expand and contract are stacked, and even if displacement occurs in the stacking direction of the battery stack S, it can maintain the function of following the displacement and detecting the terminal voltage of the battery cells C. Note that the lower part of Fig. 2 shows the deformation-following portion 4 in a shortened form, but it also indicates that the connection state is maintained by the deformation-following portion 4.

[0023] As mentioned above, the width of the main body 3 of the battery module M can be reduced. However, in a main body that integrates detection lines corresponding to all battery cells C, the width increases accordingly. Therefore, for example, in the case 50 of the battery stack S, space is required to place the main body on the surface on which the terminal rows are arranged, resulting in a larger case 50. Furthermore, if the terminals (tabs) T are made smaller to ensure space for placing the main body, their cross-sectional area decreases, increasing resistance and the temperature due to increased Joule heat.

[0024] In contrast, the above-described battery module M has fewer detection lines 3A per main body 3, which allows the width of the main body 3 to be reduced, making it easy to arrange the detection lines 3A on both sides of the terminal rows of the battery cells C and eliminating the need to increase the size of the case 50 or reduce the size of the terminals (tabs) T. As a result, the above-described battery module M is extremely useful for battery stack S structures in which the terminals T are arranged in the center of the battery cells C, in which the positions of the terminals T shift as the battery cells C are charged and discharged, and in which there is little space available.

[0025] Furthermore, the battery module M described above employs a film-like flexible printed circuit board as the detection wire bundle band 2, and is therefore deformable, allowing for easy adaptation to pattern design.

[0026] Furthermore, in the above-mentioned battery module M, the main body 2 has at least one fixed point F in the detection wire bundle band 2, and the greater the distance from the fixed point F, the greater the deformation amount of the deformation-following portion 4.Therefore, even if the battery stack S is displaced in the stacking direction and the spacing between the terminals F, F changes, the electrical connection between the main body 3 and the terminal T of the battery cell C can be maintained, and the length and deformation amount of the deformation-following portion 4 can be minimized.

[0027] Furthermore, the battery module M has a combination of a main body portion 3 and a deformation-conforming portion 4 arranged on both sides of the terminal row of the battery stack, so that a wide tab (terminal T) can be arranged near the center of the battery cell C, reducing the temperature rise of the tab when current is applied, thereby enabling a large current to flow and operation at high power.

[0028] 3 to 5 are diagrams illustrating second to fourth embodiments of the battery module according to the present invention. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0029] Second Embodiment 3 has two sets of combinations of a main body and a deformation-conforming portion 4 arranged as detection wire bundles 2 on at least one side of the terminal row of the battery cells C. In the illustrated example, two sets of combinations of a main body and a deformation-conforming portion 4 are arranged on one side (upper side) of the terminal row. The manner of connection between each deformation-conforming portion 4 and the terminal of each battery cell is the same as in the first embodiment.

[0030] The above-described battery module M can also achieve the same effects and advantages as the first embodiment, and can effectively utilize the space below the terminal row. In the illustrated example, the two sets of main bodies 3, 3 are arranged offset vertically, but by devising the arrangement of the fixing points F and the excess portion (see FIG. 2), it is possible to arrange the two sets of main bodies 3, 3 on top of each other, thereby further saving space.

[0031] Third Embodiment The battery module M shown in Figure 4 has three combinations of a main body portion 3 and a deformation-following portion 4 as detection wire bundle bands 2, with two sets arranged above the terminal row and one set arranged below the terminal row.

[0032] In the illustrated example, on the upper side of the terminal row, one set of body parts 3 has deformation-conforming parts 4 arranged thereon that connect to three terminals T from the fixed end of the battery stack S, and the other set of body parts 3 has deformation-conforming parts 4 arranged thereon that connect to two terminals T, the seventh and eighth, from the fixed end of the battery stack S. On the other hand, on the lower side of the terminal row, the body part 3 has deformation-conforming parts 4 arranged thereon that connect to the remaining terminals, i.e., the three terminals T, the fourth to sixth, from the fixed end of the battery stack S.

[0033] The above battery module M can also achieve the same functions and effects as the first embodiment. If the battery cells C were made thinner, the number of cells connected per detection line, i.e., the number of deformation-conforming portions, would increase, causing interference. In contrast, the above battery module M can increase the number of detection lines 3A to reduce the number of terminals T connected per detection line, thereby increasing the total number of battery cells C that can be connected.

[0034] <Fourth embodiment> The battery module M shown in FIG. 5 includes four detection wire bundles 2 each consisting of a main body 3 and a deformation-conforming portion 4, with two pairs arranged above and two below the terminal row.

[0035] In the illustrated example, on the upper side of the terminal row, one set of main body parts 3 has deformation-conforming parts 4 arranged thereon that connect to two terminals T from the fixed end of the battery stack S, and the other set of main body parts 3 has deformation-conforming parts 4 arranged thereon that connect to two terminals T, the fifth and sixth from the fixed end of the battery stack S.

[0036] On the other hand, on the lower side of the terminal row, one set of main body parts 3 has deformation-conforming parts 4 arranged thereon that connect to the two third and fourth terminals T from the fixed end of the battery stack S, and the other set of main body parts 3 has deformation-conforming parts 4 arranged thereon that connect to the two seventh and eighth terminals T from the fixed end of the battery stack S.

[0037] The above battery module M can also obtain the same functions and effects as the first embodiment, and compared to the third embodiment (see Figure 4), the main body portion 3 and the deformation-following portion 4 can be arranged symmetrically, making it possible to arrange the tab of the terminal T in the center while ensuring the width of the tab, and therefore the battery module M can be applied to battery modules with higher output.

[0038] The configuration of the battery module according to the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention, and the configurations of the various embodiments can also be combined. [Explanation of symbols]

[0039] C Battery cell M Battery Module S Battery stack T terminal (tab) 1 Voltage detection circuit 2 Detection line band 3 Main body (main body of detection wire bundle) 3A detection wire 4. Deformation tracking section (deformation tracking section of detection wire bundle) 4A detection wire

Claims

1. a battery stack having a structure in which a plurality of battery cells are stacked; a voltage detection circuit for detecting the terminal voltage of each of the battery cells; a flexible detection wire band for electrically connecting terminals of the individual battery cells to the voltage detection circuit; the battery stack is displaceable in the stacking direction with one end serving as a fixed end and the other end as a free end in response to expansion and contraction in the stacking direction associated with charging and discharging of the individual battery cells, and has a terminal row in which positive and negative electrode terminals protruding from the individual battery cells are arranged along the stacking direction; The detection ray bundle is a main body portion that is integrated with detection lines that are arranged along the terminal row and connected to the battery cells; a deformation-following portion that integrates detection lines that connect from the main body portion to the individual battery cells and that deforms in response to displacement of the battery stack in the stacking direction; A battery module comprising a plurality of combinations of the main body portion and the deformation-conforming portion.

2. 2. The battery module according to claim 1, wherein the detection wire bundle is a flexible printed circuit board.

3. the main body portion has at least one fixing point; The battery module according to claim 1 , wherein the deformation-conforming portions have a larger deformation amount in the stacking direction of the battery cells as the deformation-conforming portions are spaced apart from the fixed point.

4. 2. The battery module according to claim 1, wherein the combination of the main body and the deformation-conforming portion is arranged along the terminal row of the battery stack on both sides thereof.

5. 2. The battery module according to claim 1, wherein a plurality of combinations of the main body and the deformation-conforming portion are arranged on at least one side along the terminal row of the battery stack.

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