Battery pack and method for replacing secondary battery cell thereof

Abstract

This battery pack comprises: a plurality of secondary battery cells each having a cell end surface; a battery holder for storing the plurality of secondary battery cells; and a plurality of lead plates connected to the cell end surfaces of the plurality of secondary battery cells stored in the battery holder. The battery holder is provided with a storage cylinder for storing the plurality of secondary battery cells, the battery holder being equipped with a main holder in which both ends of the storage cylinder are opened, and a lid holder for closing at least a portion of the open region of the body holder. The lid holder is configured to be capable of defining a plurality of sub-holders. Each sub-holder has an electrode window opened therein, the electrode window partially exposing the cell end surface of the respective secondary battery cell, and the cell end surface is connected to any one of the plurality of lead plates via the electrode window.

Description

Battery pack and method for replacing secondary battery cells

[0001] The present disclosure relates to a battery pack and a method for replacing a secondary battery cell thereof.

[0002] Battery packs, which consist of many secondary battery cells connected in series and parallel, are used as power sources for power-assisted bicycles, power cleaners, power tools, and other portable electric devices, as stationary power storage devices for backup power sources for servers, and as power supplies for homes, offices, and factories, as well as for driving electric scooters, electric carts, and vehicles such as hybrid cars and electric automobiles.

[0003] On the other hand, in light of recent social demands such as reducing environmental impact and realizing a sustainable society, there is a demand for products that consider recycling, reusing, and reducing resources. In the case of battery packs as well, there is a demand for systems that allow for the reuse of usable parts and the replacement of deteriorated parts.

[0004] However, conventional battery packs have the problem of being difficult to reuse. For example, in a battery pack in which multiple rechargeable battery cells are housed in a battery holder and the cell ends of the rechargeable battery cells are welded to the lead plates with lead plates, removing some of the rechargeable battery cells from the battery holder and replacing them for reuse requires first removing all of the lead plates from the cell ends of each rechargeable battery cell and then removing the rechargeable battery cells from the battery holder. This process is time-consuming, and the greater the number of rechargeable battery cells and lead plates, the greater the number of lead plates that must be removed from the end faces of the rechargeable battery cells, creating a problem of increased workload.

[0005] Patent No. 4993935

[0006] One object of the present disclosure is to provide a battery pack that enables replacement of secondary battery cells and a method for replacing such secondary battery cells. Another object is to provide a battery pack that reduces the amount of work required to remove lead plates from the end faces of secondary battery cells and a method for replacing such secondary battery cells. Note that the description of these objects and objects of the present disclosure does not preclude the existence of other objects and objects. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objects. Furthermore, other objects can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0007] A battery pack according to one embodiment of the present disclosure is a battery pack comprising a plurality of secondary battery cells having cell end faces, a battery holder that houses the plurality of secondary battery cells, and a plurality of lead plates that are connected to the cell end faces of the plurality of secondary battery cells housed in the battery holder, wherein the battery holder has a storage tube that houses the plurality of secondary battery cells, and comprises a main body holder that has both ends of the storage tube open, and a lid holder that closes at least a portion of the open area of ​​the main body holder, and the lid holder is configured to be separable into a plurality of sub-holders, each of which has an electrode window that partially exposes the cell end face of the secondary battery cell, and the cell end face is connected to one of the plurality of lead plates via the electrode window.

[0008] A method for replacing secondary battery cells in a battery pack according to another aspect includes a plurality of secondary battery cells having cell end faces, a battery holder that houses the plurality of secondary battery cells, and a plurality of lead plates connected to the cell end faces of the plurality of secondary battery cells housed in the battery holder, the battery holder having a storage cylinder that houses the plurality of secondary battery cells, a main body holder that is open at both ends of the storage cylinder, and a lid holder that closes at least a portion of the open area of ​​the main body holder, the lid holder being configured to be separable into a plurality of sub-holders, each of which has an electrode window that exposes a portion of the cell end face of the secondary battery cell, and the cell end face being connected to one of the plurality of lead plates via the electrode window. the step of removing a lead plate connected to the secondary battery cell to be replaced from the lid holder and separating a sub-holder to which the removed lead plate was fixed from the lid holder; the step of removing the secondary battery cell to be replaced from the main holder; the step of inserting another secondary battery cell into the main holder in place of the secondary battery cell to be replaced; the step of fixing another sub-holder to the lid holder in place of the separated sub-holder;

[0009] As a result, when it is necessary to remove some of the secondary battery cells from the battery pack for recycling or other purposes, it is sufficient to remove only the sub-holder that blocks the cell end face of the relevant secondary battery cell, and by reducing the number of places where the connection between the cell end face of the secondary battery cell and the lead plate needs to be disconnected, it is possible to simplify the disassembly work.

[0010] 1. A perspective view showing a battery pack according to Embodiment 1. An exploded perspective view of the battery pack of FIG. 1. An exploded perspective view showing a state in which a sub-holder is being separated from the battery pack of FIG. 1. An exploded perspective view showing a state in which a new sub-holder is being attached to the battery pack of FIG. 3. A perspective view showing a battery pack according to a comparative example. An exploded perspective view of the battery pack of FIG. 5. A perspective view showing a battery pack according to Embodiment 2. An exploded perspective view of the battery pack of FIG. 7. An exploded perspective view showing a state in which a sub-holder is being separated from the battery pack of FIG. 7. A perspective view showing a battery pack according to Embodiment 3. An exploded perspective view of the battery pack of FIG. 10. A perspective view showing a battery pack according to Embodiment 4. An exploded perspective view of the battery pack of FIG. 12. A perspective view of the rear lid holder of FIG. 13. A perspective view showing a battery pack according to Embodiment 5. An exploded perspective view of the battery pack of FIG. 15. An exploded perspective view showing a state in which a sub-holder is being separated from the battery pack of FIG. 15. An exploded perspective view of the lid holder of FIG. 16. A perspective view showing a lid holder of a battery pack according to a modified example. A perspective view showing a battery pack according to Embodiment 6.

[0011] The embodiments of the present disclosure may be specified by the following configurations and features.

[0012] In a battery pack according to another aspect of the present disclosure, in the above aspect, the battery holder holds the plurality of secondary battery cells stacked in multiple stages, each sub-holder extends in the stacking direction of the plurality of secondary battery cells, and the plurality of sub-holders are arranged in a direction intersecting the extension direction of the sub-holders. With the above configuration, by extending the sub-holders in the stacking direction of the secondary battery cells, when removing some secondary battery cells, it is sufficient to remove only the sub-holder covering the row including those secondary battery cells, and it is possible to balance the number of sub-holders with the number of secondary battery cells to be disassembled, resulting in a configuration with little waste.

[0013] In addition, in the battery pack according to another aspect of the present disclosure, in any of the above aspects, the lid holder is a pair of lid holders that respectively close both sides of the open surface of the main body holder.

[0014] In addition, in a battery pack according to another aspect of the present disclosure, in any of the above aspects, the lid holder and the main body holder are formed to a size that covers the outer cans of the plurality of secondary battery cells when joined together. With this configuration, the lid holder and the main body holder can hold the plurality of secondary battery cells by sandwiching them between them.

[0015] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the lid holder connects adjacent sub-holders with breakable holder connectors. With this configuration, the sub-holders are connected in advance to form an integrated lid holder, facilitating assembly work, and when removing a secondary battery cell, the secondary battery cell can be removed by breaking only the sub-holder at the location where the secondary battery cell to be replaced is stored.

[0016] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the lid holder is configured so that the portions of the lid holder corresponding to the cell end faces of the secondary battery cells are separable as the sub-holders, and each sub-holder is formed larger than the outer shape of the cell end face. With this configuration, it is possible to remove the secondary battery cell by removing only the corresponding sub-holder without removing the lid holder itself from the main body holder.

[0017] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the lid holder has the sub-holder as a breakable thin-walled region. With this configuration, the lid holder is integrated, facilitating assembly work, and when removing a rechargeable battery cell, the rechargeable battery cell can be removed by breaking and separating only the thin-walled region where the rechargeable battery cell to be replaced is housed.

[0018] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the lead plate is bent in a stepped manner in the area corresponding to the electrode window, allowing the lead plate to be connected to the cell end face of the secondary battery cell through the electrode window of the lid holder.

[0019] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, such that multiple elements are shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0020] The battery pack of the present disclosure can be used as a driving power source for mobile objects such as power-assisted bicycles, electric carts, and electric scooters, as a power source for portable electrical devices such as radios, electric cleaners, and power tools, as a backup power source for servers in stationary power storage applications, as a power supply unit for home, office, or factory use, and as a driving power source for vehicles such as hybrid cars and electric automobiles. A battery pack used as a driving power source for a power-assisted bicycle will be described below as one embodiment of the present invention.

[0021] [Embodiment 1] A battery pack 100 according to Embodiment 1 of the present disclosure is shown in Figures 1 to 4. In these figures, Figure 1 is a perspective view showing the battery pack 100 according to Embodiment 1, Figure 2 is an exploded perspective view of the battery pack 100 of Figure 1, Figure 3 is an exploded perspective view showing a state in which a sub-holder 41 is being separated from the battery pack 100 of Figure 1, and Figure 4 is an exploded perspective view showing a state in which a new sub-holder 41 is being attached to the battery pack 100 of Figure 3. The battery pack 100 shown in these figures includes a battery holder 20, multiple secondary battery cells 1, multiple lead plates 10, and a circuit board 30. Each secondary battery cell 1 has a cell end surface 1c. Each lead plate 10 is connected to the cell end surface 1c of the multiple secondary battery cells 1 housed in the battery holder 20.

[0022] (Battery holder 20) The battery holder 20 stores and holds multiple rechargeable battery cells 1. The battery holder 20 includes a main body holder 21 and a lid holder 40. The main body holder 21 has a storage cylinder 26 that stores multiple rechargeable battery cells 1. Both ends of the storage cylinder 26 are open on the sides of the main body holder 21. The lid holder 40 closes at least a portion of the open area of ​​the main body holder 21.

[0023] The lid holder 40 is configured to be separable into multiple sub-holders 41. Each sub-holder 41 has an electrode window 42 that exposes part of the cell end face 1c of the rechargeable battery cell 1. The electrode window 42 has an opening area smaller than the cell end face 1c of the rechargeable battery cell 1. Meanwhile, as shown in Figure 2, a step is formed around the electrode window 42. By making the inner diameter of the step approximately the same as or slightly larger than the cell end face 1c, part of the edge of the rechargeable battery cell 1 can be inserted into the step for positioning.

[0024] Meanwhile, the cell end surface 1c of the secondary battery cell 1 is connected to one of the multiple lead plates 10 via the electrode window 42. With this configuration, when it is necessary to remove some of the secondary battery cells from the battery pack 100 for recycling or other purposes, it is sufficient to remove only the sub-holder 41 that closes the cell end surface of the relevant secondary battery cell. In other words, it is not necessary to disconnect the cell end surfaces from the lead plates 10 for all of the secondary battery cells included in the battery holder 20. As a result, the number of locations where the connections between the cell end surfaces and the lead plates 10 need to be disconnected is reduced, simplifying the disassembly process.

[0025] Generally, battery packs are configured by housing multiple secondary battery cells in a battery holder and welding the cell end faces of the secondary battery cells to lead plates. In light of recent societal demands for reducing environmental impact and realizing a sustainable society, systems that consider recycling, reuse, and reduction and enable the reuse of usable parts and the replacement of deteriorated parts are required. However, conventional battery packs have a problem in that they are not easily reused. Specifically, as shown in the perspective view of FIG. 5 and the exploded perspective view of FIG. 6 , the battery pack 900 has a battery holder 920 divided into a first holder 926 and a second holder 927, and multiple secondary battery cells 901 are sandwiched and housed between the first and second holders. The electrodes on the cell end faces 901c at both ends of each secondary battery cell 901 are welded to lead plates 910. A circuit board 930 is mounted on the top surface or other surface. In such a battery pack 900, if some of the secondary battery cells 901 were to be removed from the battery holder 920 and replaced for reuse, all of the lead plates 910 had to be removed from the end faces of the secondary battery cells 901 before the battery holder 920 could be disassembled and the secondary battery cells 901 could be removed from the battery holder 920. The task of removing all of the lead plates is time-consuming, and the greater the number of secondary battery cells and lead plates, the greater the number of lead plates welded to the end faces of the secondary battery cells that must be removed, resulting in a problem of increased workload.

[0026] In contrast, in the battery pack 100 according to this embodiment, as described above, the lid holder 40 is configured to be separable into a plurality of sub-holders 41, and each sub-holder 41 has an electrode window 42 that partially exposes the cell end face 1 c of the rechargeable battery cell 1. By adopting this configuration, simply removing the sub-holder 41 that covers the cell end face 1 c of the rechargeable battery cell 1 to be replaced allows access to the rechargeable battery cell 1, simplifying the disassembly work and reducing the labor required. This will be described in detail below.

[0027] (Secondary battery cells 1) The multiple secondary battery cells 1 are arranged in the battery holder 20 so that the cell end faces 1c of each secondary battery cell 1 are flush with one another. Each secondary battery cell 1 may be a cylindrical or rectangular secondary battery cell. In the example shown in Figures 1 and 2, the cylindrical secondary battery cells 1 are arranged horizontally in a lattice pattern. Note that the number and arrangement of the secondary battery cells are not limited to this example, and any number and arrangement can be used as appropriate. For example, the cylindrical secondary battery cells may be arranged in a staggered pattern.

[0028] Each secondary battery cell 1 has a positive and a negative electrode. Preferably, one of the positive and negative electrodes is provided on one cell end face of the secondary battery cell 1, and the other is provided on the other cell end face. In the example shown in FIG. 2 , the negative electrode is provided on the bottom side of the exterior can of the secondary battery cell 1, and the exterior can serves as the negative electrode. Such secondary battery cells 1 can be any known secondary battery, such as a lithium-ion secondary battery, a nickel-metal hydride battery, or a nickel-cadmium battery.

[0029] (Main Body Holder 21) The battery holder 20 includes a main body holder 21 and a lid holder 40. The main body holder 21 has multiple storage tubes 26 for storing multiple rechargeable battery cells 1. The storage tubes 26 are stacked vertically and horizontally. This allows the battery holder 20 to hold multiple stacked rechargeable battery cells 1. In the example shown in FIG. 2, a total of eight storage tubes 26 are stacked in two rows and four columns, but the number and layout of the storage tubes 26 are not limited to this configuration. The open ends of each storage tube 26 are flush with each other. Both ends of the storage tube 26 are open on one surface of the main body holder 21. In this disclosure, one surface of the main body holder 21 is referred to as the open surface 24, and the surface intersecting the open surface 24 is referred to as the peripheral surface 25. In the example shown in FIG. 2, a lid holder 40 is stacked on each open surface 24 of the main body holder 21. That is, the battery holder 20 is made up of three pieces, with one main body holder 21 sandwiched between two lid holders 40 .

[0030] Each storage cylinder 26 is cylindrical and open at both ends, allowing a rechargeable battery cell 1 having a cylindrical outer can to be inserted from either side. The interior of the storage cylinder 26 is formed to a size that can accommodate the rechargeable battery cell 1. Preferably, as shown in Figure 2 etc., the interior of the storage cylinder 26 is formed to be cylindrical so that the cylindrical outer can of the rechargeable battery cell 1 can be inserted so that cylindrical rechargeable battery cells 1 can be stored.

[0031] The main body holder 21 also has a board placement surface 23 on its top surface on which the circuit board 30 is placed. The thickness of the main body holder 21, i.e., the width of the peripheral surface 25, is shorter than the outer can of the rechargeable battery cell 1. As a result, when the rechargeable battery cell 1 is inserted into the storage tube 26 of the main body holder 21, the rechargeable battery cell 1 partially protrudes from both sides of the main body holder 21. The main body holder 21 is made of a thermoplastic resin, such as polycarbonate, polypropylene, polybutylene terephthalate, modified polyphenylene ether, ABS, or PPS. The main body holder 21 may also be divided into multiple pieces. The main body holder 21 may be divided vertically, horizontally, or in the thickness direction.

[0032] (Lid Holder 40) The lid holder 40 closes at least a portion of the open area of ​​the main body holder 21. In the example of FIG. 2 , the battery holder 20 includes a pair of lid holders 40, each closing both sides of the open surface 24 of the main body holder 21. A rechargeable battery cell 1 is inserted into each storage tube 26 of the main body holder 21, with the rechargeable battery cell 1 partially protruding from both sides of the main body holder 21. Each lid holder 40 closes each open surface 24 of the main body holder 21. Like the main body holder 21, the lid holder 40 is made of a thermoplastic resin, such as polycarbonate, polypropylene, polybutylene terephthalate, modified polyphenylene ether, ABS, or PPS. Using the same material or similar materials for the lid holder 40 and the main body holder 21 provides the advantage of making it easier to secure the main body holder 21 and the lid holder 40 together. However, the lid holder 40 and the main body holder 21 may be made of different materials.

[0033] The lid holder 40 and the main body holder 21 can be fixed together by any known method, such as special precision screws, claws, pins on one holder that are press-fitted into holes on the other holder, adhesives, heat welding, ultrasonic welding, etc. Also, to make it easier to remove the sub-holder 41 from the main body holder 21 at a later date, it is preferable to fix the lid holder 40 and the main body holder 21 in spots at positions spaced apart from each other rather than over the entire joining surface of the two.

[0034] (Sub-holders 41) The lid holder 40 is configured so that it can be separated into multiple sub-holders 41. In the example shown in FIGS. 3 and 4 , the lid holder 40 is configured with four sub-holders 41. The four sub-holders 41 are arranged on the same plane on the open surface 24 of the main body holder 21. The surface of the sub-holder 41 on which the lead plates 10 are arranged is called the lead placement surface 22. The lead placement surface 22 has electrode windows 42 that communicate with the cell end surfaces 1c to connect the lead plates 10 arranged on the outer surface of the battery holder 20 to the terminals of the rechargeable battery cells 1. In the example shown in FIGS. 3 and 4 , each sub-holder 41 has two electrode windows 42 arranged vertically. The number and arrangement pattern of the electrode windows 42 are not limited to this configuration and can be designed appropriately depending on the shape of the lead plates 10, the connection pattern of the rechargeable battery cells 1, and other factors.

[0035] Each sub-holder 41 extends in the stacking direction of the multiple rechargeable battery cells 1. In the examples shown in FIGS. 3 and 4 , each sub-holder 41 is formed in a vertically elongated rectangular shape. The multiple sub-holders 41 are arranged in a direction intersecting the extension direction of the sub-holders 41. By extending the sub-holders 41 in the stacking direction of the rechargeable battery cells 1 in this way, when removing some of the rechargeable battery cells 1, it is sufficient to remove only the sub-holders 41 covering the row including the rechargeable battery cells 1 in question. This allows for a balance between the number of sub-holders 41 and the number of rechargeable battery cells to be disassembled, resulting in a configuration with minimal waste. In the examples shown in FIGS. 3 and 4 , the vertically elongated sub-holders 41 are arranged horizontally. Therefore, the rechargeable battery cell 1 to be replaced can be extracted by removing only the sub-holder 41 with the lead plate 10 connected to it. In the example shown in FIG. 3 , the second sub-holder 41 from the right of the four sub-holders 41 and the lead plate 10 are removed, and the rechargeable battery cell 1 to be replaced is extracted. In this state, as shown in Figure 4, another secondary battery cell 1' can be inserted, the sub-holder 41 closed, and a new lead plate 10' welded to the cell end face 1c' through the electrode window 42', thereby replacing only the secondary battery cell 1 to be replaced. The sub-holder 41 may be a new sub-holder 41' of the same shape as the original sub-holder 41 or a compatible sub-holder. In the case of a lid holder 40 in which the sub-holder 41 breaks, it is preferable to replace the sub-holder 41 with a new sub-holder 41'. In this way, the battery holder 20 and circuit board 30 of the battery pack 100 in Figure 1 can be used while only some of the deteriorated secondary battery cells 1 are replaced, allowing continued use or reuse.

[0036] 3 and 4 show how only one sub-holder 41 is removed from the main holder 21 to replace two secondary battery cells 1, but the present disclosure is not limited to this configuration, and it goes without saying that it is also possible to remove multiple sub-holders to replace three or more secondary battery cells. Furthermore, any suitable method can be used to remove the lead plates, such as peeling them off or cutting them partially.

[0037] In addition, the lid holder 40 may be configured such that the sub-holders 41 are pre-separated and fixed to the main body holder 21, or such that a plurality of sub-holders 41 are integrally formed while some of the sub-holders 41 are separable.

[0038] (Lead plates 10) Lead plates 10 are arranged on the lead arrangement surface 22 of the battery holder 20. As shown in Figures 1 and 2, the lead plates 10 connect the electrodes on the cell end faces 1c of the secondary battery cells 1 to each other, connecting multiple secondary battery cells 1 in series or parallel. In the example of Figure 1, etc., eight lead plates 10 connect eight secondary battery cells 1. The number of series or parallel connections of secondary battery cells can be set as desired according to the required specifications.

[0039] Each lead plate 10 includes a base portion 11 and a lead connection piece 12 provided on a portion of the base portion 11. The lead plate 10 is bent in a stepped manner in the area corresponding to the electrode window 42. This configuration allows the lead plate 10 to be connected to the cell end surface 1c of the rechargeable battery cell 1 through the electrode window 42 of the lid holder 40. A fixing piece 14 is preferably provided in the stepped bent portion. For example, a partial cut is made in the base portion 11 to allow the L-shaped fixing piece 14 to protrude. In the example shown in FIG. 1 , two fixing pieces 14 are arranged vertically, one above the other, on the base portion 11 of each lead plate 10. The fixing pieces 14 are fixed to the cell end surface 1c of the rechargeable battery cell 1 by a known method such as spot welding, laser welding, resistance welding, or ultrasonic welding, electrically connecting the lead plate 10 to the rechargeable battery cell 1. These lead plates 10 are made of a highly conductive metal plate such as an aluminum plate, a nickel plate, or a copper plate. The base portion may also be provided with a fuse link portion that acts as a path to each fixed piece and melts in response to an overcurrent to cut off the current.

[0040] The lead plate 10 is connected to the circuit board 30 via the lead connection piece 12. The lead connection piece 12 is formed by extending from a portion of the upper end of the base portion 11. Preferably, the lead connection piece 12 is formed integrally with the base portion 11. As shown in FIG. 2, the lead plate 10, with the lead connection piece 12 protruding flush with the base portion 11, is placed on the lead placement surface 22 of the battery holder 20, and then bent as shown in FIG. 1 so that the lead connection piece 12 abuts against the connection area 32 of the circuit board 30. In this state, the lead connection piece 12 is fixed to the connection area 32. The lead connection piece 12 can also be bent in advance relative to the base portion 11.

[0041] (Circuit Board 30) The multiple secondary battery cells 1 are connected to the circuit board 30 via lead plates 10 and bus bars. The circuit board 30 is equipped with a charge / discharge circuit that charges and discharges the secondary battery cells 1, a protection circuit that monitors the voltage and temperature of the secondary battery cells 1 and cuts off the current in the event of an abnormality, and other components. The circuit board 30 is made of a glass epoxy substrate or the like. A substrate holder may also be provided as a member for holding the circuit board 30. As shown in FIGS. 1 and 2 , the circuit board 30 has multiple connection areas 32 for connecting to the lead connection pieces 12 of the multiple lead plates 10, respectively. The connection areas 32 are made of a metal material such as nickel, copper, or aluminum so that they can be electrically and mechanically connected to the lead connection pieces 12 by means such as welding. The connection areas 32 may be formed in a plate-like metal plate or in a foil pattern. The lead connection pieces 12 are connected to each of these connection areas 32 using a known connection method such as laser welding, spot welding, resistance welding, or ultrasonic welding. In this disclosure, the terms "connection" and "welding" are used to mean fixing by soldering or brazing material joining, in addition to laser welding, ultrasonic vibration welding, etc.

[0042] (Method for Replacing Secondary Battery Cells in a Battery Pack) The battery pack 100 according to this embodiment facilitates the task of replacing some of the secondary battery cells 1. As a result, in a battery pack that is unusable due to degradation of only some of the secondary battery cells 1 constituting the battery pack, the deteriorated secondary battery cells can be removed and replaced with new secondary battery cells, restoring the battery pack to a usable state. In particular, usable circuit boards and battery holders 20 can be reused to construct a new battery pack. Alternatively, usable secondary battery cells removed from a battery pack can be collected and reused when reconstructing another battery pack, and usable circuit boards can be reused. In this disclosure, reusing components constituting a battery pack in this manner is referred to as reconstructing a battery pack.

[0043] Here, the procedure for replacing some or all of the secondary battery cells in rebuilding a battery pack will be described with reference to Figures 1 to 4. When replacing, the secondary battery cells 1 to be replaced are identified in advance in the battery pack 100 shown in Figure 1. For example, the intermediate potential is measured via the lead connection pieces 12 to identify the secondary battery cells 1 with the lowest cell voltage. In this case, a group of secondary battery cells 1 connected in parallel among the secondary battery cells 1 connected to the lead plates 10 will be replaced. Here, an example will be described in which all secondary battery cells 1 connected to one lead plate 10 are replaced, i.e., two cells connected to the middle lead plate 10 in the example shown in Figure 1 etc.

[0044] From the battery pack 100 in Fig. 1, the lead-plate 10 containing the rechargeable battery cell 1 to be replaced is removed from the lead arrangement surface 22 of the lid holder 40. The example in Fig. 3 shows the state in which the lead-plate 10A, the second from the right in the figure, on the front side, is removed. In addition, to remove both rechargeable battery cells 1 connected to the lead-plate 10A, the lead-plate 10 on the far side in Fig. 3 is also removed in the same way.

[0045] Furthermore, of the multiple sub-holders 41, the sub-holder 41 to which the lead plate 10 removed from the lead placement surface 22 was fixed is separated from the lid holder 40. Note that the separation of the sub-holder 41 and the removal of the lead plate 10 may be performed simultaneously. For example, by separating the sub-holder 41, the lead plate 10 fixed on this sub-holder 41 can also be forcibly pulled off from the secondary battery cell 1.

[0046] This state makes it possible to remove the secondary battery cell 1 from the surface of the open surface 24 of the battery holder 20 where the sub-holders 41 are separated. Therefore, as shown in Fig. 3 , the secondary battery cell 1 to be replaced that was held in the separated sub-holder 41 is removed from the main holder 21. In Fig. 3 , the secondary battery cell 1A is removed from the front side of the main holder 21. It is also possible to remove and replace the secondary battery cells that were held in the same sub-holders 41 as the secondary battery cell 1A to be replaced. Alternatively, it is also possible to replace only the secondary battery cell to be replaced, and keep the secondary battery cells that were held in the same sub-holders as the secondary battery cell to be replaced.

[0047] Then, in place of the secondary battery cell 1 to be replaced, another secondary battery cell 1' is inserted into the main body holder 21. The other secondary battery cell 1' may be a new secondary battery cell, or a so-called second-hand secondary battery cell that is still usable and obtained by disassembling another battery pack or the like may be used.

[0048] Furthermore, in place of the separated sub-holder 41, another sub-holder 41' is fixed to the lid holder 40. Furthermore, in place of the removed lead plate 10, another lead plate 10' is fixed through the electrode window 42' of the other sub-holder 41'. In addition, the lead connection piece 12' at the tip of the lead plate 10' is bent and fixed to the connection area 32 of the circuit board 30. In this way, by removing only the lead plate and sub-holder 41 that belong to the secondary battery cell to be replaced, without removing all of the lead plates or the entire lid holder 40, it is possible to easily replace only a specific secondary battery cell.

[0049] [Embodiment 2] In the above-described embodiment 1, an example was described in which the battery holder 20 is configured with a main body holder 21 and two lid holders 40. However, the present disclosure is not limited to a configuration using two lid holders, and a configuration in which one lid holder is joined to the main body holder may also be used. Such an example is shown in Figures 7 to 9 as a battery pack 200 according to embodiment 2. Note that in these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0050] The battery pack 200 shown in Figures 7 and 8 has a battery holder 20B composed of one main holder 21B and one lid holder 40B. The lid holder 40B is sized to cover the exterior can of the rechargeable battery cell 1 when joined to the main holder 21B. This configuration allows the lid holder 40B and the main holder 21B to sandwich and hold multiple rechargeable battery cells 1. Furthermore, when replacing a rechargeable battery cell 1, as shown in Figure 9, the two lead plates 10 are removed and the sub-holder 41B is separated from the main holder 21B. Here, the thickness of each of the lid holder 40B and the main holder 21B is approximately half the length of the exterior can of the rechargeable battery cell 1. With this configuration, the rechargeable battery cell 1 stored in the storage cylinder 26 can be removed by only about half the length of the rechargeable battery cell 1, which is advantageous compared to the state in Figure 3 where almost the entire rechargeable battery cell 1 is housed in the storage cylinder 26.

[0051] The lid holder 40B in the second embodiment is thicker than the lid holder 40 in the first embodiment and is formed to be approximately the same thickness as the main body holder 21B. However, in this disclosure, they are referred to as the lid holder regardless of thickness. Similarly, in the second embodiment, the main body holder is not closed on both sides by two lid holders, but is closed on only one side by the lid holder 40B. This configuration is also included in the main body holder in this disclosure. Furthermore, the back side of the main body holder 21B in FIG. 8 has an electrode window that holds the secondary battery cell 1 while exposing the cell end surface 1c. This electrode window can have a shape similar to the electrode window 42 of the lid holder 40B. In this disclosure, this configuration in which the main body holder 21B has an electrode window on one side (the back side in FIG. 8 ) and the storage tube 26 is exposed on the other side (the front side in FIG. 8 ) is also used to include the main body holder with both ends of the storage tube open.

[0052] [Embodiment 3] In the above example, a configuration in which two secondary battery cells 1 are removed from a battery pack and replaced has been described, but the present disclosure is not limited to replacing two secondary battery cells, and replacement can be performed in units of three or more, or in units of one. As an example, an example in which four secondary battery cells are replaced is shown in Figures 10 and 11 as a battery pack 300 according to embodiment 3. In these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0053] The battery pack 300 shown in Figures 10 and 11 has a battery holder 20C composed of a main holder 21C and a pair of lid holders 40C that close the open surface 24 of the main holder 21C. Each lid holder 40C is composed of two sub-holders 41C. Here, each sub-holder 41C is formed in a square shape so as to close the cell end faces 1c of a total of four secondary battery cells 1, two vertically and two horizontally. Accordingly, each sub-holder 41C has four electrode windows 42. Similarly, the lead plate 10C provided on the lead placement surface 22 has a total of four fixing pieces 14, two vertically and two horizontally. The lead connection pieces 12C are provided at the upper corners of the rectangular base portion 11.

[0054] In this battery pack 300, the lead plate 10C and sub-holder 41C to which the secondary battery cell 1 to be replaced belongs are separated, and the secondary battery cell 1 to be replaced is replaced. Here, four secondary battery cells 1 including the secondary battery cell 1 to be replaced are removed from the battery holder 20C. Alternatively, only the secondary battery cell to be replaced may be replaced, and the secondary battery cells that were held in the same sub-holder as the secondary battery cell to be replaced may be maintained as they are.

[0055] Then, in place of the secondary battery cell 1 to be replaced, another secondary battery cell is inserted into the main holder 21C. Furthermore, in place of the separated sub-holder 41C, another sub-holder is fixed to the lid holder 40C. Furthermore, in place of the removed lead plate 10C, another lead plate is fixed through the electrode window 42 of the other sub-holder. In addition, the lead connection piece 12C at the tip of the lead plate 10C is bent and fixed to the connection area 32 of the circuit board 30. In this way, the secondary battery cell can be easily replaced by removing only the lead plate 10C and sub-holder 41C that belong to the secondary battery cell 1 to be replaced.

[0056] Here, an example has been shown in which the battery holder is composed of one main body holder and a pair of lid holders, as in embodiment 1, but it goes without saying that this is not limited to this and it is also possible to apply this to an example in which the battery holder is composed of one main body holder and one lid holder, as in embodiment 2.

[0057] [Embodiment 4] In each of the above embodiments, an example has been described in which the sub-holders constituting the lid holder are separated and then fixed to the main body holder. However, the present disclosure is not limited to this configuration, and the sub-holders can also be connected to form an integrated lid holder. Such an example is shown in Figures 12 to 14 as a battery pack 400 according to embodiment 4. In these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0058] 12 to 14, the battery holder 20D is composed of a main holder 21D and a pair of lid holders 40D that close the open surface 24. Each lid holder 40D has adjacent sub-holders 41D connected to each other by breakable holder connectors 44. By connecting the sub-holders 41D together in advance to form an integrated lid holder 40D, assembly work can be simplified. Furthermore, when removing a rechargeable battery cell 1, the rechargeable battery cell 1 can be removed by breaking only the sub-holder 41D that houses the rechargeable battery cell 1 to be replaced.

[0059] The holder connection portion 44 connects adjacent sub-holders 41D at one or more locations. In the example of Fig. 14, adjacent sub-holders 41D are connected at three locations that are spaced apart from each other. The locations and number of holder connection portions 44 are not limited to this example, and may be two or less or four or more. For example, the holder connection portion 44 may be provided at only one location, midway between adjacent sub-holders 41D in the vertical direction.

[0060] The holder connecting portions 44 are preferably provided integrally with the sub-holders 41D. In the example of Fig. 14, the lid holder 40D, in which four sub-holders 41D are connected by a plurality of holder connecting portions 44, is integrally molded from resin. The holder connecting portions 44 may also be configured as thin portions that are thinner than the sub-holders 41D. This makes it easier to break the sub-holders 41D from adjacent sub-holders 41D when removing them.

[0061] [Embodiment 5] In each of the above embodiments, an example has been described in which the lid holder is configured as a connected body of sub-holders. However, the present disclosure is not limited to this configuration, and a portion of the lid holder may be used as a sub-holder. Such an example is shown in Figures 15 to 18 as a battery pack 500 according to embodiment 5. In these figures, components similar to those in embodiment 1 and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0062] In the battery pack 500 shown in Figures 15 to 17, the lid holder 40E of the battery holder 20E has a detachable sub-holder 41E at the location corresponding to the cell end face 1c of the rechargeable battery cell 1. Each sub-holder 41E is larger than the outer shape of the cell end face 1c. This configuration allows the rechargeable battery cell 1 to be removed by removing only the sub-holder 41E corresponding to the rechargeable battery cell 1 to be replaced, without removing the lid holder 40E itself from the main body holder 21E. In the example shown in Figures 16 to 18, the lid holder 40E is formed in a plate shape and has a window 47 that is slightly larger than the cell end face 1c at a position corresponding to the cell end face 1c of the rechargeable battery cell 1. Furthermore, a circular sub-holder 41E is fixed to each window 47. The sub-holders 41E can be fixed to the windows 47 of the lid holder 40E by any known fixing method, such as press-fitting, fitting, adhesive, etc. Each sub-holder 41E is formed in an annular shape with an electrode window 42 opened therein.

[0063] As shown in Fig. 16 , in this battery pack 500, separate sub-holders 41E are fixed to the window portions 47 of the lid holder 40E, which press against the end faces of the rechargeable battery cells 1 to hold them in the storage tube 26 and fasten them to the fixing pieces 14 of the lead plates 10 through the electrode windows 42. When removing the rechargeable battery cell 1 to be replaced, the lead plate 10 connected to the rechargeable battery cell 1 to be replaced is removed first, as shown in Fig. 17 , and then the sub-holder 41E is removed. This makes it possible to pull out the rechargeable battery cell 1 to be replaced through the window portions 47. With this configuration, a sub-holder 41E is provided for each rechargeable battery cell 1, so it is sufficient to remove only the sub-holder 41E corresponding to the rechargeable battery cell 1 to be replaced, eliminating the need to remove the other sub-holders 41E.

[0064] In the example shown in FIG. 18 , the sub-holder 41E is a separate member from the lid holder 40E. However, the present disclosure is not limited to this configuration and the sub-holder may be integrally formed with the lid holder. For example, in the lid holder 40E′ of the battery pack according to the modified example shown in FIG. 19 , the portion corresponding to the cell end face 1c of the rechargeable battery cell 1 is formed as a breakable thin-walled region. This thin-walled region serves as a breakable sub-holder. That is, the thin-walled region corresponding to the cell end face 1c of the rechargeable battery cell 1 to be replaced is broken to open the window 47, allowing the rechargeable battery cell 1 to be removed and inserted. After insertion, the separate sub-holder 41E′ is fitted into the window 47′ and fixed in place. This configuration allows for a simple construction of the lid holder 40E′, in which the sub-holder is integrally molded in advance. Furthermore, the lid holder 40E' is integrated to facilitate assembly work, and when removing the secondary battery cell 1, the secondary battery cell 1 can be removed by breaking and separating only the thin-walled area where the secondary battery cell 1 to be replaced is stored.

[0065] Sixth Embodiment In the above-described embodiment, an example was shown in which a sub-holder was provided for each secondary battery cell, but the present disclosure is not limited to this configuration, and a sub-holder may be provided for each of a plurality of secondary battery cells, as in the first embodiment, etc. Such an example is shown in Fig. 20 as a battery pack 600 according to the sixth embodiment. In this figure, the same components as those in the first embodiment, etc., are denoted by the same reference numerals, and detailed description thereof will be omitted where appropriate.

[0066] The battery pack 600 shown in Figure 20 has a battery holder 20F composed of two parts: a main holder 21F and a lid holder 40F. Similar to Figure 8 and other figures, the main holder 21F and the lid holder 40F each have a width approximately half the length of the rechargeable battery cell 1. The lid holder 40F also has windows 47F corresponding to multiple rechargeable battery cells 1. In the example shown in Figure 20, the windows 47F are circular and slightly larger than the cell end faces 1c of two vertically adjacent rechargeable battery cells 1. The upper and lower circles are connected to form the glasses-shaped openings 47F. A step is formed at the opening edge of the window 47F. The sub-holders 41F that close each window 47F are also glasses-shaped to correspond to the glasses-shaped windows 47F. Furthermore, a flange is formed around the periphery of each sub-holder 41F, corresponding to the stepped portion of the window 47F. As a result, the flanges of each sub-holder 41F can be engaged with the stepped portions of the windows 47F, and the sub-holders 41F can be positioned and held in the windows 47 of the lid holder 40F. The sub-holders 41F and the lid holder 40F can be fixed to each other by press-fitting the sub-holders 41F into the windows 47, or by using any known fixing method, such as precision screws or adhesives, as appropriate.

[0067] Each sub-holder 41F also has an electrode window 42 opened in its circular portion. The lead plate 10 is fixed to the cell end surface 1c of the rechargeable battery cell 1 through the electrode window 42. With this configuration, as in the first embodiment, the lead plate 10 connected to the rechargeable battery cell 1 to be replaced can be removed, and the sub-holder 41F corresponding to this lead plate 10 can be removed. Then, the rechargeable battery cell 1 connected to the removed lead plate 10, including the rechargeable battery cell 1 to be replaced, can be replaced. In this battery pack 600, the sub-holder 41F is formed as a separate member from the lid holder 40F. However, as in the modified example shown in FIG. 19 , the sub-holder may be molded integrally with the lid holder, and the sub-holder may be made thin-walled to facilitate breaking, with the window portion being blocked by a separately prepared glasses-shaped sub-holder.

[0068] In the above examples, the battery pack is attached to the electrical device to be driven and supplies power to the electrical device. When the remaining capacity of the battery pack becomes low or when the battery pack deteriorates over time, the battery pack can be replaced, allowing the electrical device to continue being used. However, the present disclosure is not limited to replaceable battery packs that mainly house secondary battery cells, but can also be applied to battery packs in which secondary battery cells are housed within the housing of the electrical device. In the present disclosure, a battery pack is sufficient as long as it houses secondary battery cells within a case, and also includes battery packs in which driving secondary battery cells are built into the housing of the electrical device itself. In other words, the present disclosure is not limited to replaceable battery packs, but can also be applied to electrical devices that house secondary battery cells.

[0069] The battery pack and the method for replacing its secondary battery cells according to the present disclosure can be suitably used as a power source for driving mobile objects such as electric carts and electric scooters, and can also be suitably used as a power source for wireless devices and portable electrical devices such as electric cleaners and power tools.

[0070] DESCRIPTION OF SYMBOLS 100, 200, 300, 400, 500, 600... Battery pack 1, 1A, 1'... Secondary battery cell; 1c, 1c'... Cell end surface 10, 10', 10A, 10C... Lead plate 11... Base portion 12, 12', 12C... Lead connection piece 14... Fixing piece 20, 20B, 20C, 20D, 20E, 20F... Battery holder 21, 21B, 21C, 21D, 21E, 21F... Main body holder 22... Lead arrangement surface 23... Board arrangement surface 24... Open surface 25... Surrounding surface 26... Storage cylinder 30... Circuit board 32... Connection area 40, 40B, 40C, 40D, 40E, 40E', 40F... Lid holder 41, 41', 41A, 41B, 41C, 41D, 41E, 41E', 41F... Sub-holder 42, 42'... Electrode window 44... Holder connection portion 47, 47', 47F... Window portion 900... Battery pack 901... Secondary battery cell; 901c... Cell end surface 910... Lead plate 920... Battery holder 926... First holder 927... Second holder 930... Circuit board

Claims

1. A battery pack comprising: a plurality of secondary battery cells, each having a cell end face; a battery holder that houses the plurality of secondary battery cells; and a plurality of lead plates connected to the cell end faces of each of the plurality of secondary battery cells housed in the battery holder, wherein the battery holder has a storage tube that houses the plurality of secondary battery cells, the battery holder comprising: a main body holder with both ends open of the storage tube; and a lid holder that closes at least a portion of the open area of ​​the main body holder, the lid holder being configured to be separable into a plurality of sub-holders, each of the plurality of sub-holders having an electrode window that partially exposes the cell end face of each of the plurality of secondary battery cells, and the cell end face is connected to any of the plurality of lead plates via the electrode window.

2. A battery pack as described in claim 1, wherein the battery holder holds the secondary battery cells stacked in multiple stages, each of the multiple sub-holders extends in the stacking direction of the secondary battery cells, and the multiple sub-holders are arranged in a direction intersecting the extension direction of the sub-holders.

3. A battery pack as claimed in claim 1, wherein the cover holder is a pair of cover holders each closing either side of the open face of the main body holder.

4. A battery pack as claimed in claim 1, wherein the battery pack is formed to a size sufficient to cover the exterior cans of the multiple secondary battery cells when the lid holder and the main body holder are joined together.

5. A battery pack as claimed in claim 1, wherein the lid holder is configured such that adjacent sub-holders are connected to each other by breakable holder connecting parts.

6. A battery pack as claimed in claim 1, wherein the lid holder is configured so that the portions corresponding to the cell end faces of the secondary battery cells can be separated into the sub-holders, and each sub-holder is formed larger than the outer shape of the cell end face.

7. A battery pack according to claim 6, wherein the cover holder has the sub-holder as a breakable thin-walled area.

8. A battery pack according to any one of claims 1 to 7, wherein the lead plate is bent in a stepped manner in the area corresponding to the electrode window.

9. A method for replacing secondary battery cells of a battery pack, comprising: a plurality of secondary battery cells having cell end faces; a battery holder that houses the plurality of secondary battery cells; and a plurality of lead plates connected to the cell end faces of the plurality of secondary battery cells housed in the battery holder, wherein the battery holder has a storage tube that houses the plurality of secondary battery cells, and comprises a main body holder with both ends of the storage tube open, and a lid holder that closes at least a part of the open area of ​​the main body holder, and the lid holder is configured to be separable into a plurality of sub-holders, each of which has an electrode window that partially exposes the cell end faces of the secondary battery cells, and the battery pack has the steps of: preparing a battery pack in which the cell end face is connected to any of the plurality of lead plates via the electrode window; identifying one or more secondary battery cells to be replaced from among the plurality of secondary battery cells; a step of removing a lead plate connected to the secondary battery cell to be replaced from the lid holder, of the plurality of lead plates, and separating a sub-holder to which the removed lead plate was fixed, of the plurality of sub-holders, from the lid holder; a step of removing the secondary battery cell to be replaced from the main holder; a step of inserting another secondary battery cell into the main holder in place of the secondary battery cell to be replaced; a step of fixing the other sub-holder to the lid holder in place of the separated sub-holder; and a step of fixing the other lead plate through the electrode window of the other sub-holder in place of the removed lead plate.

10. A battery pack comprising: a plurality of secondary battery cells, each having a cell end face; a battery holder that houses the plurality of secondary battery cells; and a plurality of lead plates connected to the cell end faces of each of the plurality of secondary battery cells housed in the battery holder, wherein the battery holder comprises: an open-face main body holder with both ends open; and a lid holder that covers at least a portion of the open face of the main body holder, wherein the lid holder has a plurality of sub-holders, each of which has an electrode window that partially exposes the cell end face of the secondary battery cell, and the cell end face is connected to any of the plurality of lead plates via the electrode window.

11. A battery pack as described in claim 10, wherein the battery holder holds the multiple secondary battery cells stacked in multiple stages, each sub-holder extends in the stacking direction of the multiple secondary battery cells, and the multiple sub-holders are arranged in a direction intersecting the stacking direction of the multiple secondary battery cells.

12. A battery pack according to claim 10, wherein the lid holder is a pair of lid holders each closing either side of the open face of the main body holder.

13. A battery pack as claimed in claim 10, wherein the battery pack is formed to a size sufficient to cover the exterior cans of the plurality of secondary battery cells when the lid holder and the main body holder are joined together.

14. A battery pack as claimed in claim 10, wherein the lid holder is connected to the holder connecting portion at portions corresponding to the cell end faces of the secondary battery cells so as to be separated as the sub-holders.

15. A method for replacing secondary battery cells of a battery pack, comprising: a plurality of secondary battery cells, each having a cell end face; a battery holder that houses the plurality of secondary battery cells; and a plurality of lead plates connected to the cell end faces of the plurality of secondary battery cells housed in the battery holder, the battery holder comprising: a main body holder having an open surface that is open at both ends; and a lid holder that covers at least a portion of the open surface of the main body holder, the lid holder having a plurality of sub-holders, each of which has an electrode window that partially exposes the cell end face of the secondary battery cell, the cell end face being connected to any of the plurality of lead plates via the electrode window; and a step of identifying one or more secondary battery cells to be replaced from among the plurality of secondary battery cells. a step of removing a lead plate connected to the secondary battery cell to be replaced from among the plurality of lead plates, and separating the sub-holder, of the plurality of sub-holders, in which the removed lead plate is arranged, from the lid holder; a step of removing the secondary battery cell to be replaced from the main holder; a step of inserting another secondary battery cell into the main holder in place of the secondary battery cell to be replaced; a step of fixing a sub-holder having the same shape as the sub-holder to the lid holder; and a step of fixing another lead plate to the cell end face through the electrode window of the other sub-holder in place of the removed lead plate.

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