Battery pack having structure capable of preventing overcharging and vehicle including same

Abstract

A battery pack includes: a battery module assembly including a first battery module and a second battery module; a first connector connected to a first electrode of the first battery module; a second connector connected to a second electrode of the second battery module and spaced apart from the first connector; a switch configured to connect the first connector and the second connector; and a current blocking member connected to one side of the switch in a length direction and configured to turn off the switch by occurring a bending deformation when a potential difference formed between two electrodes of the battery module is equal to or greater than a reference value.

Description

Technical Field

[0001] This disclosure relates to a battery pack having a structure capable of preventing overcharging and a vehicle including the battery pack, and more specifically, to a battery pack including a current-blocking member and a vehicle including the battery pack, the current-blocking member being capable of blocking current between battery modules electrically connected to each other by changing the shape of the current-blocking member according to the potential difference applied between two surfaces.

[0002] This application claims priority to Korean Patent Application No. 10-2018-0138451, filed in Korea on November 12, 2018, the disclosure of which is incorporated herein by reference. Background Technology

[0003] Currently, the fusible devices used in secondary batteries include positive temperature coefficient thermistors (PTCs), thermal cut-outs (TCOs), and thermal fuses. However, thermal fuses have the disadvantage of being single-use. Although PTC thermistors or TCOs are reusable, their resistance increases with repeated use, which increases the overall resistance of the circuit.

[0004] Furthermore, all of the aforementioned devices operate by means of heat generated by overcurrent. That is, the aforementioned devices correspond to devices that operate to block current flow when an overcurrent is generated in the circuit current path due to overcharging or the like, and the temperature rises as a result.

[0005] Therefore, in the case of the aforementioned device, it is possible to block the overcurrent by operating after a situation where safety is threatened due to heat, rather than blocking the overcurrent immediately when a cause of temperature rise occurs.

[0006] Furthermore, in the case of the aforementioned devices, because they operate solely based on temperature, it is difficult to use them in secondary batteries exhibiting high output, such as those used in vehicle battery packs. In other words, in the case of vehicle battery packs, a high C-rate is required, which correspondingly requires a large amount of heat. There is a problem that devices such as PTC thermistors, thermal cut-outs (TCOs), and thermal fuses will prematurely activate when placed in such a high-temperature environment.

[0007] Therefore, there is a need for a secondary battery in which a device is reusable and usable even in environments with high current flow, and which can preemptively block the current when an event that could cause such a temperature rise occurs before the temperature rises. Summary of the Invention

[0008] Technical issues

[0009] This disclosure is designed to address problems in the related art, and therefore aims to provide a battery pack having a structure in which a current blocking member is installed, the current blocking member being able to pre-block the current before the temperature of the battery pack rises due to heat generated by overcharging of the battery pack, etc.

[0010] These and other objects and advantages of this disclosure will become apparent from the following detailed description and from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that these objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0011] Technical solution

[0012] In one aspect of this disclosure, a battery pack is provided, comprising: a battery module assembly including a first battery module and a second battery module; a first connector connected to a first electrode of the first battery module; a second connector connected to a second electrode of the second battery module and spaced apart from the first connector; a switch configured to connect the first connector and the second connector; and a current blocking member connected to one side of the switch along its length, the current blocking member being configured to disconnect (Off) the switch by bending deformation when a potential difference formed between the two electrodes of the battery module is equal to or greater than a reference value.

[0013] The battery module may include multiple battery cells that are electrically connected to each other.

[0014] One side of the switch along its length can be formed as a free end, the free end of the switch contacts the first connector and releases the contact state between the switch and the first connector by the bending deformation of the current blocking member, and the other side of the switch along its length can be formed as a fixed end fixed to the second connector.

[0015] One side of the current blocking member along its length can be a free end whose position can be changed by the bending deformation, and the other side of the current blocking member can be a fixed end that is directly or indirectly fixed to the battery module or ground.

[0016] The current blocking component may include: an electroactive polymer (EAP) layer; a first metal layer formed on one side surface of the EAP layer; and a second metal layer formed on the other side surface of the EAP layer.

[0017] The EAP layer may include at least one polymer electrolyte selected from perfluorosulfonic acid, polypyrrole, polyaniline and polythiophene.

[0018] The first metal layer and the second metal layer may include at least one metal selected from the group consisting of platinum, silver and copper.

[0019] The first metal layer can be electrically connected to the negative terminal of the battery module, and the second metal layer can be electrically connected to the positive terminal of the battery module.

[0020] The current blocking component may be located above the switch, and the first metal layer may face the switch.

[0021] The battery pack may further include a connecting rod configured to connect between the switch and the first metal layer and having non-conductive properties.

[0022] The connecting rod can be hinged to each of the switch and the first metal layer.

[0023] In another aspect of this disclosure, a vehicle is provided that includes a battery pack as described above.

[0024] Beneficial effects

[0025] According to one aspect of this disclosure, when using a battery pack, before an event such as overheating and / or explosion of the battery pack occurs due to overcharging, the current can be blocked by pre-detecting a potential difference equal to or greater than a reference value that would cause the event, thereby ensuring safety when using the battery pack. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating a battery pack according to an embodiment of the present disclosure;

[0027] Figure 2 It is shown Figure 1 A diagram showing a single battery module included in the battery pack shown;

[0028] Figure 3 It is shown Figure 2 A diagram showing a single battery cell included in the battery module shown;

[0029] Figure 4 This shows the application to Figure 1 A diagram showing the current blocking component of the battery pack;

[0030] Figure 5 It shows when in Figure 4 A diagram illustrating the shape deformation of the current blocking member when a potential difference equal to or greater than a reference value is formed between the first metal layer and the second metal layer of the current blocking member shown.

[0031] Figure 6 It is shown Figure 1 A diagram illustrating a modified example of the connection structure between the current blocking component and the connecting plate shown;

[0032] Figure 7 This is a diagram illustrating a vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0033] The preferred embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general or dictionary meaning, but rather should be interpreted based on its meaning and concept corresponding to the technical aspects of this disclosure, on the basis of allowing the inventors to appropriately define the terms to obtain the best interpretation. Therefore, the description presented herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of this disclosure; thus, it should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0034] First, refer to Figures 1 to 5 The general structure of the battery pack according to embodiments of the present disclosure will be described.

[0035] Figure 1 This is a diagram illustrating a battery pack according to an embodiment of the present disclosure. Figure 2 It is shown Figure 1 The diagram shows a single battery module included in the battery pack. Figure 3 It is shown Figure 2 The diagram shows a single battery cell included in the battery module. Furthermore, Figure 4 This shows the application to Figure 1 The diagram shows the current blocking component of the battery pack. Figure 5 It shows when in Figure 4 The diagram illustrates the shape deformation of the current blocking member when a potential difference equal to or greater than a reference value is formed between the first metal layer and the second metal layer of the current blocking member shown.

[0036] First, refer to Figure 1 The battery pack according to the embodiments of this disclosure includes a plurality of battery modules 100, a first connector 200, a second connector 300, a switch 400, a current blocking member 500, and a connecting rod 600.

[0037] Refer to together Figure 1 and Figure 2 Multiple battery modules 100 form a battery module assembly that is electrically connected to each other. Each battery module 100 may include multiple battery cells 10 connected in series, in parallel, or in a combination of series and parallel connections. Furthermore, a cell stack formed by electrically connecting the battery cells 10 may be electrically connected to a first electrode terminal 110 and a second electrode terminal 120 formed on the exterior of the battery module 100.

[0038] The accompanying drawings of this disclosure illustrate, by way of example, the case where the first electrode terminal 110 is the negative terminal and the second electrode terminal 120 is the positive terminal, but this disclosure is not limited thereto, and it is also possible for the first electrode terminal 110 to be the positive terminal and the second electrode terminal 120 to be the negative terminal.

[0039] Reference Figure 3 Each battery cell 10 included in the battery pack may, for example, be a pouch cell. (See reference...) Figure 3 The pouch-type battery cell 10 may include an electrode assembly (not shown), electrode leads 11, a cell housing 12, and sealing tape 13.

[0040] Although not shown in the accompanying drawings, the electrode assembly has a structure in which a diaphragm is inserted between alternating and repeatedly stacked positive and negative plates, and the diaphragm may be located on the two outermost sides for insulation.

[0041] The negative electrode plate includes a negative electrode current collector and a layer of negative electrode active material coated on one or both of its surfaces, and an uncoated portion of the negative electrode without the negative electrode active material is formed at one end of the plate, which serves as a negative electrode contact.

[0042] The positive electrode plate includes a positive current collector and a layer of positive active material coated on one or both of its surfaces, and an uncoated portion of the positive electrode without the positive active material is formed at one end of the plate, which serves as the positive electrode contact.

[0043] In addition, a diaphragm is inserted between the negative and positive plates to prevent direct contact between plates with different polarities. The diaphragm can be formed of a porous material to allow ion movement by using an electrolyte as a medium between the negative and positive plates.

[0044] Electrode leads 11 are connected to electrode contacts and extended to the outside of the cell housing 12. Adjacent battery cells 10 can be connected in series, in parallel, or in a combination of series and parallel via electrode leads 11 to form a single cell stack.

[0045] The unit housing 12 includes two regions: a receiving portion 12a for accommodating the electrode assembly and a sealing portion 12b. The sealing portion 12b extends along the outer periphery of the receiving portion 12a and is thermally fused together with the electrode lead 11 in the outward state to seal the unit housing 12.

[0046] Although not shown in the accompanying drawings, the unit housing 12 is sealed by bringing the edges of the upper and lower housings into contact and thermally fusion, the upper and lower housings being configured as a multilayer bag film in which resin layers / metal layers / resin layers are sequentially stacked.

[0047] Sealing tape 13 is attached to the outer periphery of the electrode lead 11 and sandwiched between the sealing portion 12b of the unit housing 12 and the electrode lead 11. Sealing tape 13 is a component used to prevent deterioration of the sealing performance of the unit housing 12 in the area where the electrode lead 11 is led out in the sealing portion 12b of the unit housing 12 due to low adhesion between the inner surface of the unit housing 12 and the electrode lead 11.

[0048] Return to reference Figure 1 The first connector 200 and the second connector 300 may be shaped like metal plates made of conductive material. The first connector 200 is fastened to the second electrode terminal 120 of a first battery module 100 located on one side of a pair of adjacent battery modules 100. Furthermore, the second connector 300 is fastened to the first electrode terminal 110 of a second battery module 100 located on the other side of a pair of adjacent battery modules 100. The first connector 200 and the second connector 300 are spaced apart from each other by a predetermined distance.

[0049] Switch 400 connects a pair of connectors 200 and 300 that are spaced apart from each other. Specifically, switch 400 can be mounted between the upper surfaces of the first connector 200 and the second connector 300.

[0050] One side of the switch 400 along its length is formed as a free end, which contacts the first connector 200 and moves together with the current blocking member 500 when it bends and deforms, thereby releasing the contact between the switch 400 and the first connector 200. In contrast, the other side of the switch 400 along its length is formed as a fixed end, which is fixed to the second connector 300 by welding or the like.

[0051] The current blocking member 500 bends when the voltage applied to the two surfaces is equal to or greater than a reference value, and the current blocking member 500 is connected to the switch 400 via a connecting rod 600 to move the switch 400 during bending deformation, thereby performing an off operation.

[0052] To perform this function, the current blocking member 500 may be disposed above the switch 400. Furthermore, one side of the current blocking member 500 along its length may be formed as a free end whose position can be changed by bending deformation, and the other side of the current blocking member 500 along its length may be formed as a fixed end that is directly or indirectly fixed to the battery module 100 or ground.

[0053] In order for the switch 400 to perform an off operation by bending and deforming the current blocking member 500, the connecting rod 600 connects the free end of the current blocking member 500 and the free end of the switch 400.

[0054] The connecting rod 600 may be formed of, for example, plastic material, and its two ends may be attached to the lower surface of the current blocking member 500 and the upper surface of the switch 400, respectively.

[0055] Additionally, refer to Figure 4 and Figure 5 In order to block overcurrent by shape deformation based on the potential difference formed between the two surfaces, the current blocking member 500 may include an electroactive polymer layer (EAP) 510, a first metal layer 520 formed on one side surface of the EAP layer 510, and a second metal layer 530 formed on the other side surface of the EAP layer 510.

[0056] EAP layer 510, namely the electroactive polymer layer, corresponds to a layer formed of a polymer electrolyte having excellent ion transfer properties, and may include, for example, at least one polymer electrolyte selected from Nafion, polypyrole, polyaniline and polythiophene.

[0057] A first metal layer 520 and a second metal layer 530 are formed on both surfaces of the EAP layer 510 and may be formed of a metal with excellent electrical conductivity. The metal layers 520 and 530 may include at least one metal selected from, for example, platinum (Pt), gold (Au), silver (Ag), and copper (Cu).

[0058] When a voltage equal to or greater than a reference value is applied through metal layers 510 and 520 formed on the two surfaces of EAP layer 510, the current blocking member 500 undergoes shape deformation.

[0059] That is, the first metal layer 520 is electrically connected to the negative terminal of the battery module 100, and the second metal layer 530 is electrically connected to the positive terminal of the battery module 100, so that a potential difference corresponding to the voltage of the battery module 100 is formed between the pair of metal layers 520 and 530.

[0060] When the potential difference formed between the pair of metal layers 520 and 530 as described above reaches a large value exceeding the safety range considering the specifications of the battery module 100 due to problems such as overcharging, migrating cations present inside the polymer electrolyte forming the EAP layer 510 hydrate in water and move along the direction of the negatively charged first metal layer 520. In this case, the imbalance of ion concentration between the first metal layer 520 and the second metal layer 530 causes osmotic pressure, which increases the amount of water molecules toward the negatively charged first metal layer 520, thus causing the current blocking member 500 to bend and deform in the direction toward the second metal layer 530.

[0061] For this shape deformation of the current blocking element 500 and the resulting operation of the switch 400, the first metal layer 520 faces the switch 400 and is connected to the negative terminal of the battery module 100, while the second metal layer 530 is connected to the positive terminal of the battery module 100.

[0062] Furthermore, the two ends of the connecting rod 600 are fixed to the first metal layer 520 and the switch 400, respectively, and are formed of a non-conductive material. This is because if the connecting rod 600 were conductive, the first metal layer 520 would be connected to both the positive and negative terminals of the battery module 100, which could cause the current blocking member 500 to bend and deform.

[0063] In addition, the magnitude of the voltage that can cause shape deformation of the current blocking member 500 varies depending on the type of polymer electrolyte constituting the EAP layer 510 applied to the current blocking member 500.

[0064] That is, the reference value of the voltage mentioned in this application may vary depending on the type of polymer electrolyte used. Therefore, a suitable polymer electrolyte can be selected based on the safe voltage range of each battery module 100 of the battery pack constituting the applied current blocking member 500, so as to quickly block the current when an event such as overcharging of the battery pack occurs.

[0065] Next, we will refer to Figure 6 describe Figure 1 This is a modified example of the connection structure between the current blocking member 500 and the switch 400 shown.

[0066] Figure 6 It is shown Figure 1 A diagram illustrating a modified example of the connection structure between the current blocking member 500 and the connecting plate.

[0067] Reference Figure 6The two ends of the connecting rod 600 can be hinged to the upper surface of the switch 400 and the first metal layer 520, respectively. Thus, when the connecting rod 600 is hinged to the switch 400 and the current blocking member 500, relative rotation is possible between the switch 400, the current blocking member 500, and the connecting rod 600. Therefore, when the free end of the current blocking member 500 moves upward due to bending deformation, the free end of the switch 400 can also move upward smoothly, without any shape deformation such as bending of the connecting rod 600.

[0068] As described above, the battery pack according to this disclosure is configured to perform on / off operations of a switch 400 electrically connected between adjacent battery modules 100 by using a current blocking member 500 that bends and deforms according to the voltage of the battery module 100, thereby ensuring safety when using the battery pack.

[0069] in addition, Figure 7 The vehicle shown in the embodiment of the present disclosure includes the battery pack as described above according to the present disclosure.

[0070] The present disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples illustrate preferred embodiments of the present disclosure, they are given by way of illustration only, as various variations and modifications within the scope of the present disclosure will become apparent to those skilled in the art based on this detailed description.

Claims

1. A battery pack, comprising: A battery module assembly including a first battery module and a second battery module; A first connector is connected to the first electrode of the first battery module; The second connector is connected to the second electrode of the second battery module and is spaced apart from the first connector; A switch configured to connect the first connector and the second connector; and A current-blocking member is connected to one side of the switch along its length, wherein the current-blocking member bends to disconnect the switch when the potential difference between two electrodes formed in the same battery module is equal to or greater than a reference value. The switch has one side along its length as a free end, which contacts the first connector and releases the contact between the switch and the first connector through the bending deformation of the current blocking member. The other side of the switch along its length is formed as a fixed end fixed to the second connector. One side of the current blocking member along its length is a free end whose position can be changed by the bending deformation, and the other side of the current blocking member along its length is a fixed end that is directly or indirectly fixed to the battery module or ground. The current-blocking member is disposed above and spaced apart from the switch, and the lower surface of the free end of the current-blocking member is connected to the upper surface of the free end of the switch via a non-conductive connecting rod, so as to move the free end of the switch upward when the current-blocking member undergoes the bending deformation, thereby performing a disconnection operation. The current blocking component includes: Electroactive polymer layer; A first metal layer is formed on one side surface of the electroactive polymer layer; and A second metal layer is formed on the other side surface of the electroactive polymer layer. The first metal layer is electrically connected to the negative electrode of the battery module, and The second metal layer is electrically connected to the positive electrode of the battery module.

2. The battery pack of claim 1, wherein the battery module comprises a plurality of battery cells electrically connected to each other.

3. The battery pack according to claim 1, wherein the electroactive polymer layer comprises at least one polymer electrolyte selected from perfluorosulfonic acid, polypyrrole, polyaniline and polythiophene.

4. The battery pack of claim 1, wherein the first metal layer and the second metal layer comprise at least one metal selected from the group consisting of platinum, silver and copper.

5. The battery pack according to claim 1, The first metal layer faces the switch.

6. The battery pack of claim 1, wherein the connecting rod is configured to connect between the switch and the first metal layer.

7. The battery pack of claim 6, wherein the connecting rod is hinged to each of the switch and the first metal layer.

8. A vehicle comprising a battery pack according to any one of claims 1 to 7.

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