BATTERY MODULE AND METHOD FOR MAKING THE SAME

Description

[0001] The invention relates firstly to a battery module comprising a stack of flat battery cells and a holder for the battery cells, wherein each of the battery cells has a contact tab that extends through the holder to an end face of the battery module, and wherein the contact tabs are connected to one another at a connection point on the end face. The invention further relates to a method for manufacturing a battery module, wherein a stack of flat battery cells, each having a contact tab, is held in a holder, and the contact tabs are extended through the holder to an end face of the battery module and connected to one another at a connection point. Documents EP3264493, E3340338, and US2013 / 052496 disclose battery modules comprising multiple battery cells and frame elements.

[0002] US 2015 / 037649 A1 proposes that, in such a battery module and a method for its manufacture, the contact tabs be detachably connected by clamping elements in order to preserve the contact tab for reusing a used battery cell in a new battery module. Previously, the contact tabs were typically welded together: To dispose of the battery module, the connection points were cut open to separate the battery cells from the holder. Due to the reduced length of the contact tab, the battery cells could subsequently not be reused in a new battery module.

[0003] Clamp connections require significant technical effort and, particularly when manufacturing electrical connections in battery modules, high precision to ensure lossless power transmission over the long term. They are also particularly susceptible to corrosion in installation situations exposed to the environment. Task

[0004] The invention is based on the objective of avoiding the disadvantages of the known prior art in the reuse of used battery cells. Solution

[0005] Based on the known battery module, the invention proposes that the contact tabs extending from the battery cells to the connection point move at least partially away from the connection point. Due to their meandering arrangement, the contact tabs of the battery cells in the battery module according to the invention have a spare length. After cutting out the connection point, the battery cell can be reused by utilizing this spare length.

[0006] Preferably, in a battery module according to the invention, the holder consists of a stack of spacer elements, wherein one of the battery cells is held in the spaces between adjacent spacer elements. Such a stacked arrangement of battery modules is generally known and proven.

[0007] Preferably, in a battery module according to the invention, adjacent spacer elements each define a channel for one of the contact tabs, guiding the contact tab in the desired direction. The channel facilitates the assembly of the battery module because the contact tabs are shaped by the geometry of the channels during stacking.

[0008] Preferably, the battery cells in a battery module according to the invention are lithium-ion batteries. Such battery modules are generally known and proven.

[0009] Preferably, in a battery module according to the invention, contact tabs of up to four battery cells are connected to one another. The connected battery cells are thus connected in parallel. In a battery module according to the invention, groups of such parallel-connected battery cells or, alternatively, individual battery cells can be connected in series.

[0010] Preferably, in a battery module according to the invention, the contact tabs are welded together at the connection point. This avoids the disadvantages of a clamp connection.

[0011] A battery cell from a battery module according to the invention can be reused by cutting out the connection point and holding the battery cell in a further holder of a further battery module and guiding it through the further holder to a head side of the further battery module, wherein the contact tab is at least partially stretched and connected at a further connection point with contact tabs of further battery modules.

[0012] Based on the known method, the invention proposes that the contact tabs, extending from the battery cells to the connection point, be laid at least sectionally away from the connection point. A method according to the invention serves to manufacture a battery module of the type described above and is also characterized by its advantages.

[0013] Preferably, in a method according to the invention, a spacer element and one of the battery cells are alternately placed on top of each other such that the spacer elements form the holder and the battery cells are held in the spaces between adjacent spacer elements. Such a sequential assembly of battery modules is generally known and proven.

[0014] Preferably, in a method according to the invention, adjacent spacer elements each define a channel for one of the contact flags, wherein the contact flag is forced in the direction away from the connection point by the superimposition of the spacer elements. The path of the contact flag is thus determined without an additional step. Example of implementation

[0015] The invention is explained below using an exemplary embodiment. Figures show... Fig. 1a / b two views of the holder of a battery module according to the invention, Fig. 2 an exploded view of the holder according to the invention, Fig. 3a / b two sectional views of the holder according to the invention, Fig. 4a / b two views of the holder of a further battery module, Fig. 5 an exploded view of the further holder, Fig. 6a / b two sectional views of the further holder.

[0016] The one in the Figure 1 The holder 1 shown in a / b, 2 and 3a / b of a battery module according to the invention, which is not further illustrated, with four battery cells connected in parallel, consists of five spacer elements 2, 3, 4, 5, 6 made of plastic.

[0017] The spacer elements 2, 3, 4, 5, 6 each have two lateral bearing blocks 7, which are connected by a bridge 8. The bearing blocks 7 each have either locking pins 11 or recesses 12 on their upper surfaces 9 and lower surfaces 10, into which the locking pins 11 engage when the battery module is mounted.

[0018] The bridges 8 each have bearings 14 for the battery cells on the inside 13 of the holder, adjacent to the blocks. On the outside 15, electrically insulating welded rails 18, 19 or shaped rails 20, 21 are attached in two connection planes 16, 17.

[0019] To manufacture the battery module according to the invention, a first battery cell is placed on a first spacer element 2, which has a first forming rail 20 in the first connection plane 16 and a first welded rail 18 in the second connection plane 17. The contact tab 22 of the first battery module is guided to the outer surface 15 via the forming rail 20 of the first spacer element 2.

[0020] Then a second spacer element 3 with two identical second form rails 21 is placed in the two connection planes 16, 17. Between the first form rail 20 of the first spacer element 2 and the second form rail 21 in the first connection plane 16, the contact tab 22 of the first battery cell is initially forced downwards in the direction away from the connection point 23. A second battery cell is placed on the second spacer element 3.

[0021] Then a third spacer element 4 is placed on top, which has only a second welded rail 19 in the first connection plane 16. The contact tab 24 of the second battery cell is forced downwards in the direction away from the connection point 23 between the second shaped rail 21 of the second spacer element 3 and the second welded rail 19. A third battery cell is placed on the third spacer element 4.

[0022] Then a fourth spacer element 5 is placed on top, which has two second forming rails 21 arranged symmetrically to the second spacer element 3. The contact tab 25 of the third battery cell is forced upwards in the direction away from the connection point 23 in the first connection plane 16 between the second welded rail 19 of the third spacer element 4 and the second forming rail 21 of the fourth spacer element 5. A fourth battery cell is placed on the fourth spacer element 5.

[0023] Finally, a fifth spacer element 6, corresponding to the first spacer element 2, is placed on top. The contact tab 26 of the fourth battery cell is forced upwards in the direction away from the connection point 23 in the first connection plane 16 between the second forming rail 21 of the fourth spacer element 5 and the first forming rail 20 of the fifth spacer element 6.

[0024] The bearing blocks 7 of the spacer elements 2, 3, 4, 5, 6 rest on top of each other in the holder 1. The battery cells are clamped between the bridges 8 and the bearings 14 by means of a tension screw (not shown) which is guided through two through holes 27 in the blocks. Finally, the contact tabs 22, 24, 25, 26 of all four battery cells are manually bent over the second welding rail 19 of the third spacer element 4 and welded there.

[0025] To dispose of a used battery module according to the invention, the connection point 23 is cut out, the four battery modules can be refurbished and disposed of using the [product / service / method] in the Figure 4a The further holder 28 shown in / b, 5 and 6a / b is reassembled into a further battery module, which is not shown further. The further holder also consists of five spacer elements 29 with shaped rails 30 and welded rails 31 in two connection planes 32.

[0026] In contrast to the holder 1 according to the invention, in the further holder the contact tabs 22, 24, 25, 26 are laid in the channels between the forming rails 30 and the welding rails 31 in smaller sections or not at all in a direction away from the connection point 33. The contact tabs 22, 24, 25, 26, which are shortened by cutting out the connection point 23 of the battery module according to the invention, can thus be welded again in the connection point 33 of the further holder 28.

[0027] Since the spacer elements 2, 3, 4, 5, 6 of the first holder 1 and the spacer elements 29 of the second holder 28 are in contact with the battery cells over a large area under high pressure, they dissipate the heat generated therein very homogeneously to the outer surface 15. Additionally, a cooling element (not shown) can be attached to the outer surface 15. The service life of the battery module according to the invention is thereby increased compared to the prior art.

[0028] The characters are 1 Holder 2 First spacer 3 Second spacer 4 Third spacer 5 Fourth spacer 6 Fifth spacer 7 Bearing block 8 Bridge 9 Top 10 Bottom 11 Detent pin 12 Recess 13 Inside 14 Bearing 15 Outside 16 First connection plane 17 Second connection plane 18 First weld rail 19 Second weld rail 20 First shaped rail 21 Second shaped rail 22 First contact lug 23 Connection point 24 Second contact lug 25 Third contact lug 26 Fourth contact lug 27 Bore 28 Holder 29 Spacer 30 Shaped rail 31 Weld rail 32 Connection plane 33 Connection point

Claims

1. A battery module with a stack of flat battery cells, and a mounting (1) for the battery cells, wherein each of the battery cells has a contact tab (22, 24, 25, 26), which is led through the mounting (1) to a head side of the battery module, and wherein the contact tabs (22, 24, 25, 26) are connected to each other on the head side at a junction (23), characterised in that, the contact tabs (22, 24, 25, 26), are routed from the battery cells to the junction (23), such that, at least in some sections, they move away from the junction (23).

2. The battery module in accordance with the preceding claim, characterised in that, the mounting (1) consists of a stack of spacer elements (2, 3, 4, 5, 6), wherein one of the battery cells is mounted in each of the spaces between neighbouring spacer elements (2, 3, 4, 5, 6).

3. The battery module in accordance with the preceding claim, characterised in that, neighbouring spacer elements (2, 3, 4, 5, 6) in each case define a channel for one of the contact tabs (22, 24, 25, 26), which guides the contact tab (22, 24, 25, 26).

4. The battery module in accordance with one of the preceding claims, characterised in that, the battery cells are lithium-ion accumulators.

5. The battery module in accordance with one of the preceding claims, characterised in that, contact tabs (22, 24, 25, 26) of up to four of the battery cells are connected to each other.

6. The battery module in accordance with one of the preceding claims, characterised in that, the contact tabs (22, 24, 25, 26) are welded together at the junction (23).

7. A method for the recycling of a battery cell from a battery module in accordance with one of the preceding claims, characterised in that, the junction (23) is cut out, and the battery cell is mounted in a further mounting (28) of a further battery module, and is guided through the further mounting (28) to a head side of the further battery module, wherein the contact tab (22, 24, 25, 26) is at least partially elongated, and is connected to contact tabs (22, 24, 25, 26) of further battery modules at a further junction (33).

8. A method for the manufacture of a battery module, wherein a stack of flat battery cells, each of which has a contact tab (22, 24, 25, 26), is mounted in a mounting (1), and the contact tabs (22, 24, 25, 26) are guided through the mounting (1) to a head side of the battery module, and connected to each other at a junction (23), characterised in that, the contact tabs (22, 24, 25, 26) are routed from the battery cells to the junction (23) such that, at least in some sections, they move away from the junction (23).

9. The method in accordance with the preceding claim, characterised in that, a spacer element (2, 3, 4, 5, 6) and one of the battery cells are placed alternately on top of each other, in such a way that the spacer elements (2, 3, 4, 5, 6) form the mounting (1), and the battery cells are held in spaces between neighbouring spacer elements (2, 3, 4, 5, 6).

10. The method in accordance with the preceding claim, characterised in that, neighbouring spacer elements (2, 3, 4, 5, 6) in each case define a channel for one of the contact tabs (22, 24, 25, 26), wherein the contact tab (22, 24, 25, 26), by the positioning of the spacer elements (2, 3, 4, 5, 6) on top of each other, is forced in the direction away from the junction (23).